{"id":31412,"date":"2023-07-06T12:41:01","date_gmt":"2023-07-06T08:11:01","guid":{"rendered":"https:\/\/wpadmin.maktabkhooneh.org\/mag\/?p=31412"},"modified":"2026-04-06T17:44:26","modified_gmt":"2026-04-06T14:14:26","slug":"let-in-javascript","status":"publish","type":"post","link":"https:\/\/maktabkhooneh.org\/mag\/let-in-javascript\/","title":{"rendered":"\u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0648 \u06a9\u0627\u0631\u0628\u0631\u062f\u0647\u0627\u06cc \u0622\u0646"},"content":{"rendered":"\n<p>\u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\u060c \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u00ablet\u00bb \u0628\u0631\u0627\u06cc \u0627\u0639\u0644\u0627\u0645 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc\u06cc \u0628\u0627 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0627\u06a9 (Block Scope) \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc\u200c\u0634\u0648\u062f. \u0627\u06cc\u0646 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u062f\u0631 \u0646\u0633\u062e\u0647 ES2015\/ES6 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0647 \u0647\u0645\u0631\u0627\u0647 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u00abconst\u00bb \u0645\u0639\u0631\u0641\u06cc \u0634\u062f. \u062f\u0631 \u0627\u06cc\u0646 \u0645\u0637\u0644\u0628 \u0627\u0632 \u0645\u062c\u0644\u0647 \u0645\u06a9\u062a\u0648\u0628 \u0645\u06cc\u200c\u062e\u0648\u0627\u0647\u06cc\u0645 \u062f\u0631 \u0631\u0627\u0628\u0637\u0647 \u0628\u0627 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0648 \u0631\u0633\u0627\u0644\u062a \u0622\u0646 \u062a\u0648\u0636\u06cc\u062d\u0627\u062a\u06cc \u06a9\u0627\u0645\u0644 \u0648 \u062c\u0627\u0645\u0639 \u0627\u0631\u0627\u0626\u0647 \u06a9\u0646\u06cc\u0645. \u067e\u0633 \u0628\u0627 \u0645\u0627 \u0647\u0645\u0631\u0627\u0647 \u0628\u0627\u0634\u06cc\u062f.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0686\u06cc\u0633\u062a\u061f<\/h2>\n\n\n\n<p>\u0642\u0628\u0644 \u0627\u0632 ES2015\/ES6\u060c \u062a\u0646\u0647\u0627 \u062f\u0648 \u0646\u0648\u0639 \u062f\u0627\u0645\u0646\u0647 \u0645\u062a\u063a\u06cc\u0631 \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\u060c \u0645\u062d\u062f\u0648\u062f\u0647 \u0633\u0631\u0627\u0633\u0631\u06cc \u06cc\u0627 \u062c\u0647\u0627\u0646\u06cc (Global Scope) \u0648 \u0645\u062d\u062f\u0648\u062f\u0647 \u06cc\u0627 \u062f\u0627\u0645\u0646\u0647 \u062a\u0627\u0628\u0639\u06cc (Functions Scope) \u0648\u062c\u0648\u062f \u062f\u0627\u0634\u062a\u0646\u062f. \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc\u06cc \u06a9\u0647 \u0628\u0627 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u00abvar\u00bb \u0627\u0639\u0644\u0627\u0645 \u0645\u06cc\u200c\u0634\u0648\u0646\u062f\u060c \u0645\u062d\u062f\u0648\u062f\u0647 \u062a\u0627\u0628\u0639\u06cc \u062f\u0627\u0631\u0646\u062f\u060c \u0628\u0647 \u0627\u06cc\u0646 \u0645\u0639\u0646\u06cc \u06a9\u0647 \u062f\u0631 \u062a\u0627\u0628\u0639\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u0627\u0639\u0644\u0627\u0646 \u0634\u062f\u0647\u200c\u0627\u0646\u062f\u060c \u06cc\u0627 \u0627\u06af\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u0647\u0631 \u062a\u0627\u0628\u0639\u06cc \u0627\u0639\u0644\u0627\u0645 \u0634\u0648\u062f\u060c \u062f\u0631 \u0633\u0631\u0627\u0633\u0631 \u062f\u0627\u0645\u0646\u0647 \u062c\u0647\u0627\u0646\u06cc \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u0647\u0633\u062a\u0646\u062f. \u062f\u0631 \u0632\u06cc\u0631 \u0633\u06cc\u0646\u062a\u06a9\u0633 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0631\u0627\u06cc \u0627\u0639\u0644\u0627\u0645 \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 \u0622\u0645\u062f\u0647 \u0627\u0633\u062a:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token keyword\">let<\/span> variable_name<span class=\"token punctuation\">;<\/span><\/code><\/pre>\n\n\n\n<p>\u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9 \u0631\u0627 \u0645\u0639\u0631\u0641\u06cc \u06a9\u0631\u062f\u060c \u0628\u0647 \u0627\u06cc\u0646 \u0645\u0639\u0646\u06cc \u06a9\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc \u0627\u0639\u0644\u0627\u0645 \u0634\u062f\u0647 \u0628\u0627 let \u0628\u0647 \u0628\u0644\u0648\u06a9\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u062a\u0639\u0631\u06cc\u0641 \u0634\u062f\u0647\u200c\u0627\u0646\u062f \u0645\u062d\u062f\u0648\u062f \u0645\u06cc\u200c\u0634\u0648\u0646\u062f. \u0628\u0644\u0648\u06a9 \u0647\u0631 \u06a9\u062f\u06cc \u0627\u0633\u062a \u06a9\u0647 \u062f\u0631 \u067e\u0631\u0627\u0646\u062a\u0632\u0647\u0627\u06cc \u00ab{}\u00bb \u0646\u0648\u0634\u062a\u0647 \u0634\u062f\u0647 \u0628\u0627\u0634\u062f. \u0645\u062b\u0627\u0644 \u0632\u06cc\u0631 \u0645\u062d\u062f\u0648\u0647 \u0628\u0644\u0648\u06a9\u06cc \u0631\u0627 \u0646\u0634\u0627\u0646 \u0645\u06cc\u200c\u062f\u0647\u062f:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token punctuation\">{<\/span>\n\n  <span class=\"token keyword\">let<\/span> x <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f1\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n  console<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f1\u06f0<\/span>\n\n<span class=\"token punctuation\">}<\/span>\n\nconsole<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ ReferenceError: x is not defined<\/span><\/code><\/pre>\n\n\n\n<p>\u062f\u0631 \u0645\u062b\u0627\u0644 \u0628\u0627\u0644\u0627\u060c \u0645\u062a\u063a\u06cc\u0631 \u00abx\u00bb \u0628\u0627 \u00ablet\u00bb \u062f\u0631 \u062f\u0627\u062e\u0644 \u06cc\u06a9 \u0628\u0644\u0648\u06a9 \u0627\u0639\u0644\u0627\u0645 \u0634\u062f\u0647 \u0648 \u0641\u0642\u0637 \u062f\u0631 \u0622\u0646 \u0628\u0644\u0648\u06a9 \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u0627\u0633\u062a. \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9\u060c \u062a\u0644\u0627\u0634 \u0628\u0631\u0627\u06cc \u062f\u0633\u062a\u0631\u0633\u06cc \u0628\u0647 &#8220;x&#8221; \u0645\u0646\u062c\u0631 \u0628\u0647 \u00ab\u062e\u0637\u0627\u06cc \u0645\u0631\u062c\u0639 ReferenceError\u00bb \u0645\u06cc\u200c\u0634\u0648\u062f. \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u00ablet\u00bb \u0627\u062c\u0627\u0632\u0647 \u0645\u06cc\u200c\u062f\u0647\u062f \u062a\u0627 \u06a9\u0646\u062a\u0631\u0644 \u062f\u0642\u06cc\u0642\u200c\u062a\u0631\u06cc \u0628\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u0645\u062a\u063a\u06cc\u0631 \u062f\u0627\u0634\u062a\u0647 \u0628\u0627\u0634\u062f \u0648 \u0628\u0647 \u062c\u0644\u0648\u06af\u06cc\u0631\u06cc \u0627\u0632 \u0645\u0634\u06a9\u0644\u0627\u062a \u0631\u0627\u06cc\u062c \u0645\u0631\u062a\u0628\u0637 \u0628\u0627 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc \u0627\u0639\u0644\u0627\u0645 \u0634\u062f\u0647 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u00abvar\u00bb\u060c \u0645\u0627\u0646\u0646\u062f \u0628\u0627\u0644\u0627 \u0628\u0631\u062f\u0646 \u062a\u0635\u0627\u062f\u0641\u06cc \u0645\u062a\u063a\u06cc\u0631 (Hiosting \u06a9\u0631\u062f\u0646) \u06cc\u0627 \u0646\u0634\u062a \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0628\u0647 \u062f\u0627\u0645\u0646\u0647 \u062c\u0647\u0627\u0646\u06cc \u06a9\u0645\u06a9 \u0645\u06cc\u200c\u06a9\u0646\u062f. \u062f\u0631 \u06a9\u0644 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0631\u0627\u06cc \u0627\u0639\u0644\u0627\u0645 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0628\u0627 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc\u200c\u0634\u0648\u062f \u0648 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0622\u0646 \u0627\u0637\u0645\u06cc\u0646\u0627\u0646 \u062d\u0627\u0635\u0644 \u062e\u0648\u0627\u0647\u062f \u0634\u062f \u06a9\u0647 \u0622\u0646\u200c\u0647\u0627 \u0628\u0647 \u0628\u0644\u0648\u06a9\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u062a\u0639\u0631\u06cc\u0641 \u0634\u062f\u0647\u200c\u0627\u0646\u062f \u0645\u062d\u062f\u0648\u062f \u0645\u06cc\u200c\u0634\u0648\u0646\u062f.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u0645\u062b\u0627\u0644\u200c \u0647\u0627\u06cc\u06cc \u0628\u0631\u0627\u06cc Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a<\/h2>\n\n\n\n<p>\u062f\u0631 \u0627\u06cc\u0646 \u0628\u062e\u0634 \u0686\u0646\u062f \u0645\u062b\u0627\u0644 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0647\u200c\u0645\u0646\u0638\u0648\u0631 \u062f\u0631\u06a9 \u0628\u0647\u062a\u0631 \u0627\u06cc\u0646 \u0645\u0641\u0647\u0648\u0645 \u0622\u0648\u0631\u062f\u0647 \u0634\u062f\u0647 \u0627\u0633\u062a. \u0645\u062b\u0627\u0644\u200c\u0647\u0627\u06cc \u0622\u0648\u0631\u062f\u0647 \u0634\u062f\u0647 \u0647\u0631\u06a9\u062f\u0627\u0645 \u0645\u0631\u062a\u0628\u0637 \u0628\u0627 \u0645\u0641\u0647\u0648\u0645 \u062e\u0627\u0635\u06cc \u062d\u0648\u0644 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc Let \u062f\u0631 Javascript \u0647\u0633\u062a\u0646\u062f \u0648 \u0627\u0647\u0645\u06cc\u062a \u0632\u06cc\u0627\u062f\u06cc \u062f\u0631 \u062f\u0631\u06a9 \u0622\u0646 \u062f\u0627\u0631\u0646\u062f.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u0645\u062b\u0627\u0644 \u06f1. \u0645\u062d\u062f\u0648\u062f\u0647 \u0633\u0631\u0627\u0633\u0631\u06cc<\/h3>\n\n\n\n<p>\u0645\u062b\u0627\u0644 \u0632\u06cc\u0631 \u0645\u0641\u0647\u0645\u062f\u0645 \u0645\u062d\u062f\u0648\u062f\u0647 \u06cc\u0627 \u062f\u0627\u0645\u0646\u0647 \u0633\u0631\u0627\u0633\u0631\u06cc \u0631\u0627 \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u06cc\u0627\u0646 \u0645\u06cc\u200c\u06a9\u0646\u062f \u06a9\u0647 \u0642\u0637\u0639\u0647 \u06a9\u062f \u0622\u0646 \u0628\u0647 \u0635\u0648\u0631\u062a \u0632\u06cc\u0631 \u0627\u0633\u062a:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token operator\">&lt;<\/span>script<span class=\"token operator\">&gt;<\/span>\n\n<span class=\"token keyword\">let<\/span> x <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f2\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\ndocument<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"Outside the function x = \"<\/span> <span class=\"token operator\">+<\/span> x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n\n<span class=\"token keyword\">function<\/span> <span class=\"token function\">show<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\n\n    document<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"&lt;br&gt; Inside the function x = \"<\/span> <span class=\"token operator\">+<\/span> x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token punctuation\">}<\/span>\n\n<span class=\"token function\">show<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token operator\">&lt;<\/span><span class=\"token operator\">\/<\/span>script<span class=\"token operator\">&gt;<\/span><\/code><\/pre>\n\n\n\n<p>\u062e\u0631\u0648\u062c\u06cc \u0645\u062b\u0627\u0644 \u0641\u0648\u0642 \u062f\u0631 \u062f\u0627\u062e\u0644 \u06a9\u0646\u0633\u0648\u0644 \u0628\u0647 \u0635\u0648\u0631\u062a \u0632\u06cc\u0631 \u0627\u0633\u062a:<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter\"><img fetchpriority=\"high\" decoding=\"async\" width=\"502\" height=\"195\" src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword1.png\" alt=\"\u0622\u0645\u0648\u0632\u0634 Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\" class=\"wp-image-31413\" title=\"\" srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword1.png 502w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2023\/07\/javascript-let-keyword1-300x117.png.webp 300w\" sizes=\"(max-width: 502px) 100vw, 502px\" \/><figcaption><\/figcaption><\/figure>\n\n\n\n<p>\u062f\u0631 \u0627\u06cc\u0646 \u0645\u062b\u0627\u0644\u060c \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 x \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u062c\u0647\u0627\u0646\u06cc \u0627\u0639\u0644\u0627\u0645 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645. \u0645\u062a\u063a\u06cc\u0631 x \u0627\u0632 \u0647\u0631 \u062c\u0627\u06cc\u06cc \u062f\u0631 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u0627\u0633\u062a. \u0648\u0642\u062a\u06cc \u062a\u0627\u0628\u0639 show()\u200e \u0631\u0627 \u0641\u0631\u0627\u062e\u0648\u0627\u0646\u06cc \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645\u060c \u0645\u0642\u062f\u0627\u0631 x \u0631\u0627 \u0647\u0645 \u062f\u0631 \u062e\u0627\u0631\u062c \u0648 \u0647\u0645 \u062f\u0631 \u062f\u0627\u062e\u0644 \u062a\u0627\u0628\u0639 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0645\u062a\u062f document.write()\u200e \u0646\u0645\u0627\u06cc\u0634 \u0645\u06cc\u200c\u062f\u0647\u062f. \u0627\u0632 \u0622\u0646\u062c\u0627\u06cc\u06cc \u06a9\u0647 x \u062f\u0631 \u062f\u0627\u0645\u0646\u0647 \u062c\u0647\u0627\u0646\u06cc \u062a\u0639\u0631\u06cc\u0641 \u0634\u062f\u0647 \u0627\u0633\u062a\u060c \u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u0627\u0632 \u062e\u0627\u0631\u062c \u0648 \u062f\u0627\u062e\u0644 \u062a\u0627\u0628\u0639 \u0628\u062f\u0648\u0646 \u0647\u06cc\u0686 \u0645\u0634\u06a9\u0644\u06cc \u0628\u0647 \u0622\u0646 \u062f\u0633\u062a\u0631\u0633\u06cc \u062f\u0627\u0634\u062a.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u0645\u062b\u0627\u0644 \u06f2. \u0645\u062d\u062f\u0648\u062f\u0647 \u062a\u0627\u0628\u0639\u06cc<\/h3>\n\n\n\n<p>\u0641\u0627\u0646\u06a9\u0634\u0646 \u0627\u0633\u06a9\u0648\u067e \u06cc\u0627 \u0645\u062d\u062f\u0648\u062f\u0647 <a href=\"https:\/\/maktabkhooneh.org\/mag\/functions-in-javascript\/\">Function \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a<\/a> \u0646\u06cc\u0632 \u06cc\u06a9\u06cc \u0627\u0632 \u0645\u0641\u0627\u0647\u06cc\u0645 \u0645\u0631\u0628\u0648\u0637\u0647 \u0628\u0647 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0627\u0633\u062a \u06a9\u0647 \u0645\u062b\u0627\u0644 \u0632\u06cc\u0631 \u0648 \u062a\u0648\u0636\u06cc\u062d\u0627\u062a \u0622\u0646 \u0628\u0631\u0627\u06cc \u062f\u0631\u06a9 \u0627\u06cc\u0646 \u0645\u0641\u0647\u0648\u0645 \u0622\u0648\u0631\u062f\u0647 \u0634\u062f\u0647 \u0627\u0633\u062a:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token operator\">&lt;<\/span>script<span class=\"token operator\">&gt;<\/span>\n\n<span class=\"token keyword\">function<\/span> <span class=\"token function\">show<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\n\n    <span class=\"token keyword\">let<\/span> num <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f1\u06f5<\/span><span class=\"token punctuation\">;<\/span>\n\n    document<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"Inside the function num = \"<\/span> <span class=\"token operator\">+<\/span> num<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token punctuation\">}<\/span>\n\n<span class=\"token function\">show<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\ndocument<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"&lt;br&gt; Outside the function num = \"<\/span> <span class=\"token operator\">+<\/span> num<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token operator\">&lt;<\/span><span class=\"token operator\">\/<\/span>script<span class=\"token operator\">&gt;<\/span><\/code><\/pre>\n\n\n\n<p>\u062f\u0631 \u0627\u06cc\u0646 \u0645\u062b\u0627\u0644\u060c \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 num \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062a\u0627\u0628\u0639 show()\u200e \u0627\u0639\u0644\u0627\u0645 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645. \u0645\u062a\u063a\u06cc\u0631 num \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u062a\u0627\u0628\u0639 \u0627\u0633\u062a\u060c \u0628\u0647 \u0627\u06cc\u0646 \u0645\u0639\u0646\u06cc \u06a9\u0647 \u0641\u0642\u0637 \u062f\u0631 \u062f\u0627\u062e\u0644 \u062a\u0627\u0628\u0639 \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u062e\u0648\u0627\u0647\u062f \u0628\u0648\u062f. \u0648\u0642\u062a\u06cc \u062a\u0627\u0628\u0639 show()\u200e \u0631\u0627 \u0641\u0631\u0627\u062e\u0648\u0627\u0646\u06cc \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645\u060c \u0645\u0642\u062f\u0627\u0631 num \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0645\u062a\u062f document.write()\u200e \u0646\u0645\u0627\u06cc\u0634 \u0645\u06cc\u200c\u062f\u0647\u062f. \u0628\u0627 \u0627\u06cc\u0646 \u062d\u0627\u0644\u060c \u0632\u0645\u0627\u0646\u06cc \u06a9\u0647 \u0633\u0639\u06cc \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645 \u0628\u0647 \u0645\u062a\u063a\u06cc\u0631 num \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u062a\u0627\u0628\u0639 \u062f\u0633\u062a\u0631\u0633\u06cc \u067e\u06cc\u062f\u0627 \u06a9\u0646\u06cc\u0645\u060c \u06cc\u06a9 \u062e\u0637\u0627 \u0627\u06cc\u062c\u0627\u062f \u0645\u06cc\u200c\u06a9\u0646\u062f \u0632\u06cc\u0631\u0627 num \u062f\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u06cc\u0631\u0648\u0646\u06cc \u062a\u0639\u0631\u06cc\u0641 \u0646\u0634\u062f\u0647 \u0627\u0633\u062a. \u062e\u0631\u0648\u062c\u06cc \u0627\u06cc\u0646 \u0645\u062b\u0627\u0644 \u0628\u0647 \u0635\u0648\u0631\u062a \u0632\u06cc\u0631 \u062e\u0648\u0627\u0647\u062f \u0628\u0648\u062f:<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter\"><img decoding=\"async\" width=\"502\" height=\"203\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword2.png\" alt=\"\u0644\u062a \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\" class=\"wp-image-31414 lazyload\" title=\"\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword2.png 502w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2023\/07\/javascript-let-keyword2-300x121.png.webp 300w\" data-sizes=\"(max-width: 502px) 100vw, 502px\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 502px; --smush-placeholder-aspect-ratio: 502\/203;\" \/><figcaption><\/figcaption><\/figure>\n\n\n\n<p>\u0647\u0645\u0686\u0646\u06cc\u0646 \u062f\u0631 \u0627\u06cc\u0646 \u0645\u062b\u0627\u0644\u060c \u0627\u06af\u0631 \u06a9\u062f \u0631\u0627 \u0627\u062c\u0631\u0627 \u0648 \u062e\u0631\u0648\u062c\u06cc \u06a9\u0646\u0633\u0648\u0644 \u0631\u0627 \u0628\u0631\u0631\u0633\u06cc \u06a9\u0646\u06cc\u062f\u060c \u0628\u0627 \u062e\u0637\u0627\u06cc \u0632\u06cc\u0631 \u0645\u0648\u0627\u062c\u0647 \u062e\u0648\u0627\u0647\u06cc\u062f \u0634\u062f:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Uncaught ReferenceError<span class=\"token operator\">:<\/span> num is not defined<\/code><\/pre>\n\n\n\n<p>\u067e\u06cc\u0627\u0645 \u062e\u0637\u0627 \u0646\u0634\u0627\u0646 \u0645\u06cc\u200c\u062f\u0647\u062f \u06a9\u0647 ReferenceError \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f \u0632\u06cc\u0631\u0627 \u0645\u062a\u063a\u06cc\u0631 num \u062f\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u06cc\u0631\u0648\u0646\u06cc \u062a\u0639\u0631\u06cc\u0641 \u0646\u0634\u062f\u0647 \u0627\u0633\u062a. \u0627\u06cc\u0646 \u062e\u0637\u0627 \u0632\u0645\u0627\u0646\u06cc \u0631\u062e \u0645\u06cc\u200c\u062f\u0647\u062f \u06a9\u0647 \u0633\u0639\u06cc \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645 \u0628\u0647 \u0645\u062a\u063a\u06cc\u0631\u06cc \u06a9\u0647 \u0627\u0639\u0644\u0627\u0645 \u0646\u0634\u062f\u0647 \u06cc\u0627 \u062e\u0627\u0631\u062c \u0627\u0632 \u0645\u062d\u062f\u0648\u062f\u0647 \u0627\u0633\u062a \u062f\u0633\u062a\u0631\u0633\u06cc \u067e\u06cc\u062f\u0627 \u06a9\u0646\u06cc\u0645.<\/p>\n\n\n\n<p>\u062e\u0637 document.write(&#8220;&lt;br&gt; Outside the function num = &#8221; + num);\u200e \u062f\u0631 \u062d\u0627\u0644 \u062a\u0644\u0627\u0634 \u0628\u0631\u0627\u06cc \u062f\u0633\u062a\u0631\u0633\u06cc \u0628\u0647 \u0645\u062a\u063a\u06cc\u0631 num \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u062a\u0627\u0628\u0639 show()\u200e \u0627\u0633\u062a\u060c \u0627\u0645\u0627 \u0627\u0632 \u0622\u0646\u062c\u0627\u06cc\u06cc \u06a9\u0647 num \u0628\u0627 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062f\u0627\u062e\u0644 \u062a\u0627\u0628\u0639 \u0627\u0639\u0644\u0627\u0646 \u0645\u06cc\u200c\u0634\u0648\u062f\u060c \u062a\u0646\u0647\u0627 \u062f\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u062a\u0627\u0628\u0639 \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u0627\u0633\u062a. \u062f\u0631 \u0646\u062a\u06cc\u062c\u0647\u060c \u0647\u0646\u06af\u0627\u0645 \u062a\u0644\u0627\u0634 \u0628\u0631\u0627\u06cc \u062f\u0633\u062a\u0631\u0633\u06cc \u0628\u0647 num \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u062a\u0627\u0628\u0639\u060c \u062e\u0637\u0627 \u0631\u062e \u0645\u06cc\u200c\u062f\u0647\u062f \u0648 \u0639\u0628\u0627\u0631\u062a \u062f\u0648\u0645 \u0686\u0627\u067e \u0646\u0645\u06cc\u200c\u0634\u0648\u062f.<\/p>\n\n\n\n<p>\u0644\u0637\u0641\u0627\u064b \u062a\u0648\u062c\u0647 \u062f\u0627\u0634\u062a\u0647 \u0628\u0627\u0634\u06cc\u062f \u06a9\u0647 \u0645\u0639\u0645\u0648\u0644\u0627\u064b \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 document.write()\u200e \u0628\u0631\u0627\u06cc \u0646\u0645\u0627\u06cc\u0634 \u062e\u0631\u0648\u062c\u06cc \u062a\u0648\u0635\u06cc\u0647 \u0646\u0645\u06cc\u200c\u0634\u0648\u062f\u060c \u0632\u06cc\u0631\u0627 \u062f\u0631 \u0635\u0648\u0631\u062a \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u067e\u0633 \u0627\u0632 \u0628\u0627\u0631\u06af\u06cc\u0631\u06cc \u0633\u0646\u062f \u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u062f \u06a9\u0644 \u0633\u0646\u062f \u0631\u0627 \u0628\u0627\u0632\u0646\u0648\u06cc\u0633\u06cc \u06a9\u0646\u062f. \u062f\u0631 \u0633\u0646\u0627\u0631\u06cc\u0648\u0647\u0627\u06cc \u062f\u0646\u06cc\u0627\u06cc \u0648\u0627\u0642\u0639\u06cc\u060c \u0645\u0639\u0645\u0648\u0644\u0627\u064b \u0627\u0632 \u0631\u0648\u0634\u200c\u0647\u0627\u06cc \u062f\u06cc\u06af\u0631\u06cc \u0645\u0627\u0646\u0646\u062f \u062f\u0633\u062a\u06a9\u0627\u0631\u06cc DOM \u06cc\u0627 \u0648\u0631\u0648\u062f \u0628\u0647 \u06a9\u0646\u0633\u0648\u0644 \u0628\u0631\u0627\u06cc \u0646\u0645\u0627\u06cc\u0634 \u062e\u0631\u0648\u062c\u06cc \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645.<\/p>\n\n\n<div class=\"jet-listing-grid--50192\" style=\"\"><style><\/style><section class=\"zht-related-post\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Article\" role=\"region\"\n  aria-label=\"Related article\">\n  <div class=\"zht-related-post-section-label\">\n    \u0645\u0637\u0627\u0644\u0628 \u0645\u0631\u062a\u0628\u0637\n  <\/div>\n  <img decoding=\"async\" width=\"300\" height=\"150\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/06\/azhvn8vuqrofsidykaas-300x150.webp\" class=\"attachment-medium size-medium wp-post-image lazyload\" alt=\"\u0622\u0645\u0648\u0632\u0634 class \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/06\/azhvn8vuqrofsidykaas-300x150.webp 300w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/06\/azhvn8vuqrofsidykaas-768x384.webp 768w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/06\/azhvn8vuqrofsidykaas.webp 1000w\" data-sizes=\"(max-width: 300px) 100vw, 300px\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 300px; --smush-placeholder-aspect-ratio: 300\/150;\">\n  <a href=\"https:\/\/maktabkhooneh.org\/mag\/class-in-js\/\" class=\"zht-related-post-title\"\n    itemprop=\"headline\" target=\"_blank\">\u0622\u0645\u0648\u0632\u0634 class \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0647 \u0632\u0628\u0627\u0646 \u0633\u0627\u062f\u0647<\/a>\n<\/section><\/div>\n\n\n<h3 class=\"wp-block-heading\">\u0645\u062b\u0627\u0644 \u06f3. \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc<\/h3>\n\n\n\n<p>\u0645\u062d\u062f\u0648\u0647 \u062f\u06cc\u06af\u0631\u06cc \u06a9\u0647 \u062f\u0631 \u0631\u0627\u0628\u0637\u0647 \u0628\u0627 \u0645\u0641\u0647\u0648\u0645 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0627\u0647\u0645\u06cc\u062a \u0632\u06cc\u0627\u062f\u06cc \u062f\u0627\u0631\u062f \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc &nbsp;\u06cc\u0627 \u0647\u0645\u0627\u0646 \u0628\u0644\u0648\u06a9 \u0627\u0633\u06a9\u0648\u067e \u0627\u0633\u062a \u06a9\u0647 \u062f\u0631 \u0642\u0627\u0644\u0628 \u0645\u062b\u0627\u0644 \u0632\u06cc\u0631 \u062a\u0648\u0636\u06cc\u062d \u062f\u0627\u062f\u0647 \u062e\u0648\u0627\u0647\u062f \u0634\u062f.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token operator\">&lt;<\/span>script<span class=\"token operator\">&gt;<\/span>\n\n<span class=\"token punctuation\">{<\/span>\n\n    <span class=\"token keyword\">let<\/span> num <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f3\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n    document<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"Inside the block num = \"<\/span> <span class=\"token operator\">+<\/span> num<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token punctuation\">}<\/span>\n\ndocument<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"&lt;br&gt; Outside the block num = \"<\/span> <span class=\"token operator\">+<\/span> num<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token operator\">&lt;<\/span><span class=\"token operator\">\/<\/span>script<span class=\"token operator\">&gt;<\/span><\/code><\/pre>\n\n\n\n<p>\u062f\u0631 \u0627\u06cc\u0646 \u0645\u062b\u0627\u0644\u060c \u0645\u0627 \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 num \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u062f\u0631 \u062f\u0627\u062e\u0644 \u06cc\u06a9 \u0628\u0644\u0648\u06a9 \u0627\u0639\u0644\u0627\u0645 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645. \u0645\u062a\u063a\u06cc\u0631 num \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc \u0627\u0633\u062a\u060c \u0628\u0647 \u0627\u06cc\u0646 \u0645\u0639\u0646\u06cc \u06a9\u0647 \u0641\u0642\u0637 \u062f\u0631 \u0628\u0644\u0648\u06a9\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u062a\u0639\u0631\u06cc\u0641 \u0634\u062f\u0647 \u0627\u0633\u062a \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u0627\u0633\u062a. \u062f\u0631 \u062f\u0627\u062e\u0644 \u0628\u0644\u0648\u06a9\u060c \u0627\u0632 document.write()\u200e \u0628\u0631\u0627\u06cc \u0646\u0645\u0627\u06cc\u0634 \u0645\u0642\u062f\u0627\u0631 num \u0628\u0647 \u0635\u0648\u0631\u062a &#8220;Inside the block num = 30&#8221; \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645. \u0628\u0627 \u0627\u06cc\u0646 \u062d\u0627\u0644\u060c \u0647\u0646\u06af\u0627\u0645\u06cc \u06a9\u0647 \u0645\u0627 \u0633\u0639\u06cc \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645 \u0628\u0647 num \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9 \u062f\u0633\u062a\u0631\u0633\u06cc \u067e\u06cc\u062f\u0627 \u06a9\u0646\u06cc\u0645\u060c \u06cc\u06a9 \u062e\u0637\u0627 \u0627\u06cc\u062c\u0627\u062f \u0645\u06cc\u200c\u06a9\u0646\u062f \u0632\u06cc\u0631\u0627 num \u062f\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u06cc\u0631\u0648\u0646\u06cc \u062a\u0639\u0631\u06cc\u0641 \u0646\u0634\u062f\u0647 \u0627\u0633\u062a.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter\"><img decoding=\"async\" width=\"583\" height=\"187\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword3.png\" alt=\"Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\" class=\"wp-image-31415 lazyload\" title=\"\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword3.png 583w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2023\/07\/javascript-let-keyword3-300x96.png.webp 300w\" data-sizes=\"(max-width: 583px) 100vw, 583px\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 583px; --smush-placeholder-aspect-ratio: 583\/187;\" \/><figcaption><\/figcaption><\/figure>\n\n\n\n<p>\u062f\u0633\u062a\u0648\u0631 \u062f\u0648\u0645 document.write()\u200e \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9 \u0645\u0642\u062f\u0627\u0631 num \u0631\u0627 \u0646\u0645\u0627\u06cc\u0634 \u0646\u0645\u06cc\u200c\u062f\u0647\u062f \u0632\u06cc\u0631\u0627 \u062f\u0631 \u0622\u0646 \u0645\u062d\u062f\u0648\u062f\u0647 \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u0646\u06cc\u0633\u062a \u0648 \u062e\u0637\u0627\u06cc \u0632\u06cc\u0631 \u0631\u0627 \u0645\u06cc\u200c\u062f\u0647\u062f:<\/p>\n\n\n\n<div class=\"elementor elementor-9853\" data-elementor-type=\"wp-post\" data-elementor-id=\"9853\">\n<div class=\"elementor-inner\">\n<div class=\"elementor-section-wrap\">\n<section class=\"elementor-section elementor-top-section elementor-element elementor-element-733fcde elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"733fcde\" data-element_type=\"section\">\n<div class=\"elementor-container elementor-column-gap-default\">\n<div class=\"elementor-row\">\n<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-42e7506\" data-id=\"42e7506\" data-element_type=\"column\">\n<div class=\"elementor-column-wrap elementor-element-populated\">\n<div class=\"elementor-widget-wrap\">\n<div class=\"elementor-element elementor-element-62a27ae elementor-widget elementor-widget-code-highlight\" data-id=\"62a27ae\" data-element_type=\"widget\" data-widget_type=\"code-highlight.default\">\n<div class=\"elementor-widget-container\">\n<div class=\"prismjs-default copy-to-clipboard \">\n<div class=\"code-toolbar\">\n<pre class=\"highlight-height language-javascript\" data-line=\"\"><code class=\" language-javascript\">UncaughtReferenceError<span class=\"token operator\">:<\/span> num is not defined<\/code><\/pre>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"saboxplugin-wrap\">\n<div class=\"saboxplugin-tab\"><\/div>\n<\/div>\n\n\n\n<p>\u0647\u0645\u0627\u0646\u200c\u0637\u0648\u0631 \u06a9\u0647 \u0645\u06cc\u200c\u0628\u06cc\u0646\u06cc\u062f\u060c \u0645\u0642\u062f\u0627\u0631 num \u0628\u0647 \u062f\u0631\u0633\u062a\u06cc \u062f\u0631 \u062f\u0627\u062e\u0644 \u0628\u0644\u0648\u06a9 \u0646\u0645\u0627\u06cc\u0634 \u062f\u0627\u062f\u0647 \u0645\u06cc\u200c\u0634\u0648\u062f\u060c \u0627\u0645\u0627 \u0632\u0645\u0627\u0646\u06cc \u06a9\u0647 \u0633\u0639\u06cc \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645 \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9 \u0628\u0647 \u0622\u0646 \u062f\u0633\u062a\u0631\u0633\u06cc \u067e\u06cc\u062f\u0627 \u06a9\u0646\u06cc\u0645\u060c \u0645\u0646\u062c\u0631 \u0628\u0647 ReferenceError \u0645\u06cc\u200c\u0634\u0648\u062f \u0632\u06cc\u0631\u0627 num \u0641\u0642\u0637 \u062f\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9 \u062a\u0639\u0631\u06cc\u0641 \u0645\u06cc\u200c\u0634\u0648\u062f.<\/p>\n\n\n<div class=\"jet-listing-grid--50192\" style=\"\"><section class=\"zht-related-post\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Article\" role=\"region\"\n  aria-label=\"Related article\">\n  <div class=\"zht-related-post-section-label\">\n    \u0645\u0637\u0627\u0644\u0628 \u0645\u0631\u062a\u0628\u0637\n  <\/div>\n  <img decoding=\"async\" width=\"300\" height=\"150\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2023\/06\/6288755792019456-300x150.jpeg.webp\" class=\"attachment-medium size-medium wp-post-image lazyload\" alt=\"append \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2023\/06\/6288755792019456-300x150.jpeg.webp 300w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2023\/06\/6288755792019456-768x384.jpeg.webp 768w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/06\/6288755792019456.jpeg 1024w\" data-sizes=\"(max-width: 300px) 100vw, 300px\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 300px; --smush-placeholder-aspect-ratio: 300\/150;\">\n  <a href=\"https:\/\/maktabkhooneh.org\/mag\/append-in-javascript\/\" class=\"zht-related-post-title\"\n    itemprop=\"headline\" target=\"_blank\">\u0622\u0645\u0648\u0632\u0634 \u0645\u062a\u062f append \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0647 \u0632\u0628\u0627\u0646 \u0633\u0627\u062f\u0647<\/a>\n<\/section><\/div>\n\n\n<h3 class=\"wp-block-heading\">\u0645\u062b\u0627\u0644 \u06f4. \u0627\u0639\u0644\u0627\u0646 \u0645\u062c\u062f\u062f \u0645\u062a\u063a\u06cc\u0631 \u062f\u0631 \u0628\u0644\u0648\u06a9\u200c\u0647\u0627\u06cc \u0645\u062e\u062a\u0644\u0641<\/h3>\n\n\n\n<p>\u0645\u062b\u0627\u0644 \u0632\u06cc\u0631 \u0647\u0645 \u0628\u0647\u200c\u0645\u0646\u0638\u0648\u0631 \u0627\u0639\u0644\u0627\u0646 \u0645\u062a\u063a\u06cc\u0631 \u062f\u0631 \u0628\u0644\u0648\u06a9\u200c\u0647\u0627\u06cc \u0645\u062e\u062a\u0644\u0641 \u0622\u0648\u0631\u062f\u0647 \u0634\u062f\u0647 \u0627\u0633\u062a:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token operator\">&lt;<\/span>script<span class=\"token operator\">&gt;<\/span>\n\n<span class=\"token keyword\">let<\/span> num <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f2\u06f3<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token punctuation\">{<\/span>\n\n    <span class=\"token keyword\">let<\/span> num <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f1\u06f5<\/span><span class=\"token punctuation\">;<\/span>\n\n    document<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"num inside the block = \"<\/span> <span class=\"token operator\">+<\/span> num<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token punctuation\">}<\/span>\n\n<span class=\"token keyword\">let<\/span> num <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f8\u06f9<\/span><span class=\"token punctuation\">;<\/span>\n\ndocument<span class=\"token punctuation\">.<\/span><span class=\"token function\">write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">\"&lt;br&gt; num outside the block = \"<\/span> <span class=\"token operator\">+<\/span> num<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token operator\">&lt;<\/span><span class=\"token operator\">\/<\/span>script<span class=\"token operator\">&gt;<\/span><\/code><\/pre>\n\n\n\n<p>\u062f\u0631 \u0627\u062c\u0631\u0627\u06cc \u06a9\u062f \u0628\u0627\u0644\u0627\u060c \u0627\u06cc\u0646 \u06cc\u06a9 \u062e\u0637\u0627 \u0627\u06cc\u062c\u0627\u062f \u0645\u06cc\u200c\u06a9\u0646\u062f \u0632\u06cc\u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0645\u062a\u063a\u06cc\u0631 let\u060c \u0627\u0639\u0644\u0627\u0645 \u0645\u062c\u062f\u062f \u0645\u062c\u0627\u0632 \u0646\u06cc\u0633\u062a\u061b \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646\u060c \u0647\u06cc\u0686 \u062e\u0631\u0648\u062c\u06cc \u062f\u0631 \u0645\u0631\u0648\u0631\u06af\u0631 \u0646\u0645\u0627\u06cc\u0634 \u0646\u0645\u06cc\u200c\u062f\u0647\u062f.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter\"><img decoding=\"async\" width=\"585\" height=\"184\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword4.png\" alt=\"\u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\" class=\"wp-image-31416 lazyload\" title=\"\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/javascript-let-keyword4.png 585w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2023\/07\/javascript-let-keyword4-300x94.png.webp 300w\" data-sizes=\"(max-width: 585px) 100vw, 585px\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 585px; --smush-placeholder-aspect-ratio: 585\/184;\" \/><figcaption><\/figcaption><\/figure>\n\n\n\n<p>\u0627\u06af\u0631 \u062e\u0631\u0648\u062c\u06cc \u06a9\u0646\u0633\u0648\u0644 \u0631\u0627 \u0645\u0634\u0627\u0647\u062f\u0647 \u06a9\u0631\u062f\u06cc\u062f\u060c \u062e\u0637\u0627\u06cc \u0627\u06cc\u062c\u0627\u062f \u0634\u062f\u0647 \u062f\u0631 \u0627\u062c\u0631\u0627\u06cc \u0627\u06cc\u0646 \u0628\u0631\u0646\u0627\u0645\u0647 \u0631\u0627 \u0646\u0634\u0627\u0646 \u0645\u06cc\u200c\u062f\u0647\u062f.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SyntaxError<span class=\"token operator\">:<\/span> redeclaration <span class=\"token keyword\">of<\/span> <span class=\"token keyword\">let<\/span> x\n\nnote<span class=\"token operator\">:<\/span> Previously declared at line <span class=\"token number\">\u06f2<\/span><span class=\"token punctuation\">,<\/span> column <span class=\"token number\">\u06f5<\/span><\/code><\/pre>\n\n\n\n<p>\u067e\u06cc\u0627\u0645 \u062e\u0637\u0627 \u0646\u0634\u0627\u0646 \u0645\u06cc\u200c\u062f\u0647\u062f \u06a9\u0647 \u06cc\u06a9 SyntaxError \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f \u0632\u06cc\u0631\u0627 \u0645\u062a\u063a\u06cc\u0631 num \u062f\u0631 \u062d\u0627\u0644 \u0627\u0639\u0644\u0627\u0645 \u0645\u062c\u062f\u062f \u0627\u0633\u062a. \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0647 \u0645\u0627 \u0627\u062c\u0627\u0632\u0647 \u0645\u06cc\u200c\u062f\u0647\u062f \u06a9\u0647 \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 \u0631\u0627 \u0628\u0627 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9 \u0627\u0639\u0644\u0627\u0645 \u06a9\u0646\u06cc\u0645\u060c \u0627\u0645\u0627 \u0627\u062c\u0627\u0632\u0647 \u0646\u0645\u06cc\u200c\u062f\u0647\u062f \u06a9\u0647 \u0646\u0627\u0645 \u0645\u062a\u063a\u06cc\u0631 \u0645\u0634\u0627\u0628\u0647 \u062f\u0631 \u0647\u0645\u0627\u0646 \u0645\u062d\u062f\u0648\u062f\u0647 \u0627\u0639\u0644\u0627\u0645 \u0634\u0648\u062f. \u062f\u0631 \u06a9\u062f \u0627\u0631\u0627\u0626\u0647 \u0634\u062f\u0647 \u062f\u0648 \u0627\u0639\u0644\u0627\u0646 num \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0627\u0631\u06cc\u0645. \u0627\u0639\u0644\u0627\u0646 \u0627\u0648\u0644 \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9 \u0648 \u0627\u0639\u0644\u0627\u0646 \u062f\u0648\u0645 \u062f\u0627\u062e\u0644 \u0628\u0644\u0648\u06a9 \u0627\u0633\u062a. \u0628\u0627 \u0627\u06cc\u0646 \u062d\u0627\u0644\u060c \u0627\u0632 \u0622\u0646\u062c\u0627\u06cc\u06cc \u06a9\u0647 \u0647\u0631 \u062f\u0648 \u0627\u0639\u0644\u0627\u0646 \u0646\u0627\u0645 \u0645\u062a\u063a\u06cc\u0631 \u06cc\u06a9\u0633\u0627\u0646\u06cc \u062f\u0627\u0631\u0646\u062f\u060c \u0645\u0646\u062c\u0631 \u0628\u0647 \u06cc\u06a9 \u062e\u0637\u0627\u06cc \u0646\u062d\u0648\u06cc \u0645\u06cc\u200c\u0634\u0648\u062f.<\/p>\n\n\n\n<p>\u062f\u0631 \u0646\u062a\u06cc\u062c\u0647 \u0647\u06cc\u0686 \u062e\u0631\u0648\u062c\u06cc \u062f\u0631 \u0645\u0631\u0648\u0631\u06af\u0631 \u0646\u0645\u0627\u06cc\u0634 \u062f\u0627\u062f\u0647 \u0646\u0645\u06cc\u200c\u0634\u0648\u062f \u0648 \u06a9\u0646\u0633\u0648\u0644 \u062e\u0637\u0627\u06cc \u0646\u062d\u0648\u06cc \u0631\u0627 \u0628\u0627 \u06cc\u0627\u062f\u062f\u0627\u0634\u062a\u06cc \u0646\u0634\u0627\u0646 \u0645\u06cc\u200c\u062f\u0647\u062f \u06a9\u0647 \u0646\u0634\u0627\u0646 \u0645\u06cc\u200c\u062f\u0647\u062f \u0645\u062a\u063a\u06cc\u0631 \u0642\u0628\u0644\u0627\u064b \u062f\u0631 \u06cc\u06a9 \u062e\u0637 \u0648 \u0633\u062a\u0648\u0646 \u062e\u0627\u0635 \u0627\u0639\u0644\u0627\u0645 \u0634\u062f\u0647 \u0627\u0633\u062a. \u0628\u0631\u0627\u06cc \u0631\u0641\u0639 \u0627\u06cc\u0646 \u0645\u0634\u06a9\u0644\u060c \u0647\u0646\u06af\u0627\u0645 \u0627\u0639\u0644\u0627\u0646 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u062f\u0631 \u0645\u062d\u062f\u0648\u062f\u0647 \u06cc\u06a9\u0633\u0627\u0646\u060c \u0627\u0637\u0645\u06cc\u0646\u0627\u0646 \u062d\u0627\u0635\u0644 \u06a9\u0646\u06cc\u062f \u06a9\u0647 \u0627\u0632 \u0646\u0627\u0645 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc \u0645\u0646\u062d\u0635\u0631\u0628\u0647\u200c\u0641\u0631\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u062f.<\/p>\n\n\n<div class=\"jet-listing-grid--50192\" style=\"\"><section class=\"zht-related-post\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Article\" role=\"region\"\n  aria-label=\"Related article\">\n  <div class=\"zht-related-post-section-label\">\n    \u0645\u0637\u0627\u0644\u0628 \u0645\u0631\u062a\u0628\u0637\n  <\/div>\n  <img decoding=\"async\" width=\"300\" height=\"186\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2022\/05\/05-04-21-getting-started-with-javascript-constructor-functions-blog-300x186.jpg.webp\" class=\"attachment-medium size-medium wp-post-image lazyload\" alt=\"\u062a\u0627\u0628\u0639 \u0633\u0627\u0632\u0646\u062f\u0647 \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0686\u06cc\u0633\u062a\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2022\/05\/05-04-21-getting-started-with-javascript-constructor-functions-blog-300x186.jpg.webp 300w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2022\/05\/05-04-21-getting-started-with-javascript-constructor-functions-blog-768x476.jpg.webp 768w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2022\/05\/05-04-21-getting-started-with-javascript-constructor-functions-blog.jpg 1024w\" data-sizes=\"(max-width: 300px) 100vw, 300px\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 300px; --smush-placeholder-aspect-ratio: 300\/186;\">\n  <a href=\"https:\/\/maktabkhooneh.org\/mag\/javascript-constructor-functions\/\" class=\"zht-related-post-title\"\n    itemprop=\"headline\" target=\"_blank\">\u062a\u0648\u0627\u0628\u0639 \u0633\u0627\u0632\u0646\u062f\u0647 \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a<\/a>\n<\/section><\/div>\n\n\n<h2 class=\"wp-block-heading\">\u062a\u0641\u0627\u0648\u062a \u06a9\u0644\u0645\u0627\u062a \u06a9\u0644\u06cc\u062f\u06cc Var \u0648 Let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a<\/h2>\n\n\n\n<p>\u062a\u0641\u0627\u0648\u062a \u0627\u0635\u0644\u06cc \u0628\u06cc\u0646 \u06a9\u0644\u0645\u0627\u062a \u06a9\u0644\u06cc\u062f\u06cc let \u0648 var \u062f\u0631 \u062f\u0627\u0645\u0646\u0647 \u0622\u0646\u200c\u0647\u0627 \u0646\u0647\u0641\u062a\u0647 \u0627\u0633\u062a. \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc var \u062f\u0627\u0631\u0627\u06cc \u06cc\u06a9 \u062f\u0627\u0645\u0646\u0647 \u062c\u0647\u0627\u0646\u06cc \u0628\u0648\u062f\u0647 \u062f\u0631\u062d\u0627\u0644\u06cc\u200c\u06a9\u0647 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0627\u0631\u0627\u06cc \u06cc\u06a9 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc \u0627\u0633\u062a. \u0628\u0631\u0627\u06cc \u062f\u0631\u06a9 \u0627\u06cc\u0646 \u062a\u0641\u0627\u0648\u062a \u0645\u062b\u0627\u0644\u200c\u0647\u0627\u06cc \u0632\u06cc\u0631 \u0631\u0627 \u062f\u0631 \u0646\u0638\u0631 \u0645\u06cc\u200c\u06af\u06cc\u0631\u06cc\u0645:<\/p>\n\n\n\n<p><strong>\u0645\u062b\u0627\u0644 \u06f1: \u0645\u062d\u062f\u0648\u062f\u0647 \u062c\u0647\u0627\u0646\u06cc \u06cc\u0627 \u0633\u0631\u0627\u0633\u0631\u06cc:<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token keyword\">var<\/span> x <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f1\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token keyword\">let<\/span> y <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f2\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n<span class=\"token keyword\">function<\/span> <span class=\"token function\">example<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\n\n  console<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f1\u06f0<\/span>\n\n  console<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>y<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f2\u06f0<\/span>\n\n<span class=\"token punctuation\">}<\/span>\n\n<span class=\"token function\">example<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n\nconsole<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f1\u06f0<\/span>\n\nconsole<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>y<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ ReferenceError: y is not defined<\/span><\/code><\/pre>\n\n\n\n<p>\u062f\u0631 \u0627\u06cc\u0646 \u0645\u062b\u0627\u0644\u060c \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 x \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc var \u0648 \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 y \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u0627\u0639\u0644\u0627\u0645 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645. \u0645\u062a\u063a\u06cc\u0631 var x \u062f\u0627\u0631\u0627\u06cc \u06cc\u06a9 \u062f\u0627\u0645\u0646\u0647 \u062c\u0647\u0627\u0646\u06cc \u0627\u0633\u062a\u060c \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u0627\u0632 \u0647\u0631 \u0646\u0642\u0637\u0647 \u062f\u0631 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0647 \u0622\u0646 \u062f\u0633\u062a\u0631\u0633\u06cc \u062f\u0627\u0634\u062a. \u0628\u0627 \u0627\u06cc\u0646 \u062d\u0627\u0644\u060c \u0645\u062a\u063a\u06cc\u0631 let y \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc \u0627\u0633\u062a \u0648 \u0641\u0642\u0637 \u062f\u0631 \u0628\u0644\u0648\u06a9\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u062a\u0639\u0631\u06cc\u0641 \u0634\u062f\u0647 \u0627\u0633\u062a \u0642\u0627\u0628\u0644\u200c\u062f\u0633\u062a\u0631\u0633\u06cc \u0627\u0633\u062a\u061b \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646\u060c \u062a\u0644\u0627\u0634 \u0628\u0631\u0627\u06cc \u062f\u0633\u062a\u0631\u0633\u06cc \u0628\u0647 y \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9 \u0645\u0646\u062c\u0631 \u0628\u0647 \u06cc\u06a9 ReferenceError \u0645\u06cc\u200c\u0634\u0648\u062f.<\/p>\n\n\n\n<p><strong>\u0645\u062b\u0627\u0644 \u06f2: Block Scope \u06cc\u0627 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc:<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code><span class=\"token keyword\">function<\/span> <span class=\"token function\">example<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\n\n  <span class=\"token keyword\">var<\/span> x <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f1\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n  <span class=\"token keyword\">let<\/span> y <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f2\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n  <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token boolean\">true<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>\n\n    <span class=\"token keyword\">var<\/span> x <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f3\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n    <span class=\"token keyword\">let<\/span> y <span class=\"token operator\">=<\/span> <span class=\"token number\">\u06f4\u06f0<\/span><span class=\"token punctuation\">;<\/span>\n\n    console<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f3\u06f0<\/span>\n\n    console<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>y<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f4\u06f0<\/span>\n\n  <span class=\"token punctuation\">}<\/span>\n\n  console<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>x<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f3\u06f0<\/span>\n\n  console<span class=\"token punctuation\">.<\/span><span class=\"token function\">log<\/span><span class=\"token punctuation\">(<\/span>y<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ \u06f2\u06f0<\/span>\n\n<span class=\"token punctuation\">}<\/span>\n\n<span class=\"token function\">example<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/code><\/pre>\n\n\n\n<p>\u062f\u0631 \u0627\u06cc\u0646 \u0645\u062b\u0627\u0644\u060c \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 x \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc var \u0648 \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 y \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062a\u0627\u0628\u0639 example() \u0627\u0639\u0644\u0627\u0645 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645. \u062f\u0631 \u062f\u0627\u062e\u0644 \u0628\u0644\u0648\u06a9 \u062f\u0633\u062a\u0648\u0631 if\u060c x \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 var \u0648 y \u0631\u0627 \u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 let \u062f\u0648\u0628\u0627\u0631\u0647 \u0627\u0639\u0644\u0627\u0645 \u0645\u06cc\u200c\u06a9\u0646\u06cc\u0645. \u0627\u0632 \u0622\u0646\u062c\u0627\u06cc\u06cc \u06a9\u0647 var \u06cc\u06a9 \u0645\u062d\u062f\u0648\u062f\u0647 \u062a\u0627\u0628\u0639\u06cc \u062f\u0627\u0631\u062f\u060c \u0627\u0639\u0644\u0627\u0645 \u0645\u062c\u062f\u062f x \u062f\u0631 \u062f\u0627\u062e\u0644 \u0628\u0644\u0648\u06a9 \u0628\u0631 \u0645\u0642\u062f\u0627\u0631 x \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9 \u0646\u06cc\u0632 \u062a\u0623\u062b\u06cc\u0631 \u0645\u06cc\u200c\u06af\u0630\u0627\u0631\u062f. \u0627\u0632 \u0637\u0631\u0641 \u062f\u06cc\u06af\u0631\u060c \u0645\u062a\u063a\u06cc\u0631 let y \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc \u0627\u0633\u062a\u060c \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646 \u0627\u0639\u0644\u0627\u0645 \u0645\u062c\u062f\u062f \u0622\u0646 \u062f\u0631 \u062f\u0627\u062e\u0644 \u0628\u0644\u0648\u06a9 \u0628\u0631 \u0645\u0642\u062f\u0627\u0631 y \u062f\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u0628\u0644\u0648\u06a9 \u062a\u0623\u062b\u06cc\u0631 \u0646\u0645\u06cc\u200c\u06af\u0630\u0627\u0631\u062f. \u0628\u0647\u200c\u0637\u0648\u0631 \u062e\u0644\u0627\u0635\u0647\u060c \u062a\u0641\u0627\u0648\u062a\u200c\u0647\u0627\u06cc \u0627\u0635\u0644\u06cc \u0628\u06cc\u0646 let \u0648 var \u0639\u0628\u0627\u0631\u062a\u200c\u0627\u0646\u062f \u0627\u0632:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc \u0628\u0648\u062f\u0647 \u0648 \u0627\u0632 \u0637\u0631\u0641\u06cc \u062f\u06cc\u06af\u0631 var \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u062a\u0627\u0628\u0639 \u0627\u0633\u062a.<\/li>\n\n\n\n<li>\u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc var \u0631\u0627 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u062f\u0631 \u0647\u0645\u0627\u0646 \u0645\u062d\u062f\u0648\u062f\u0647 \u0645\u062c\u062f\u062f\u0627\u064b \u0627\u0639\u0644\u0627\u0645 \u06a9\u0631\u062f\u060c \u062f\u0631\u062d\u0627\u0644\u06cc\u200c\u06a9\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc let \u0631\u0627 \u0646\u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u062f\u0631 \u06cc\u06a9 \u0628\u0644\u0648\u06a9 \u0645\u062c\u062f\u062f\u0627\u064b \u0627\u0639\u0644\u0627\u0645 \u06a9\u0631\u062f.<\/li>\n<\/ul>\n\n\n\n<p>\u062f\u0631\u06a9 \u0627\u06cc\u0646 \u062a\u0641\u0627\u0648\u062a\u200c\u0647\u0627 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u062f \u0628\u0647 \u0634\u0645\u0627 \u06a9\u0645\u06a9 \u06a9\u0646\u062f \u062a\u0627 \u0628\u0627 \u0627\u0646\u062a\u062e\u0627\u0628 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u0645\u0646\u0627\u0633\u0628 \u0628\u0631 \u0627\u0633\u0627\u0633 \u0645\u062d\u062f\u0648\u062f\u0647 \u0648 \u0631\u0641\u062a\u0627\u0631 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc \u062e\u0648\u062f \u06a9\u062f \u0642\u0648\u06cc\u200c\u062a\u0631 \u0648 \u0642\u0627\u0628\u0644 \u067e\u06cc\u0634\u200c\u0628\u06cc\u0646\u06cc \u0628\u06cc\u0634\u062a\u0631\u06cc \u0628\u0646\u0648\u06cc\u0633\u06cc\u062f.<\/p>\n\n\n<div class=\"jet-listing-grid--50192\" style=\"\"><section class=\"zht-related-post\" itemscope=\"\" itemtype=\"https:\/\/schema.org\/Article\" role=\"region\"\n  aria-label=\"Related article\">\n  <div class=\"zht-related-post-section-label\">\n    \u0645\u0637\u0627\u0644\u0628 \u0645\u0631\u062a\u0628\u0637\n  <\/div>\n  <img decoding=\"async\" width=\"300\" height=\"184\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2022\/04\/73b42386-b4f8-4a39-9899-c4272d4702e4-300x184.jpg.webp\" class=\"attachment-medium size-medium wp-post-image lazyload\" alt=\"\u0635\u0641\u0631 \u062a\u0627 \u0635\u062f \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2022\/04\/73b42386-b4f8-4a39-9899-c4272d4702e4-300x184.jpg.webp 300w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/smush-webp\/2022\/04\/73b42386-b4f8-4a39-9899-c4272d4702e4-768x472.jpg.webp 768w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2022\/04\/73b42386-b4f8-4a39-9899-c4272d4702e4.jpg 1024w\" data-sizes=\"(max-width: 300px) 100vw, 300px\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 300px; --smush-placeholder-aspect-ratio: 300\/184;\">\n  <a href=\"https:\/\/maktabkhooneh.org\/mag\/variable-in-javascript\/\" class=\"zht-related-post-title\"\n    itemprop=\"headline\" target=\"_blank\">\u0635\u0641\u0631 \u062a\u0627 \u0635\u062f \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a<\/a>\n<\/section><\/div>\n\n\n<h2 class=\"wp-block-heading\">\u062a\u0641\u0627\u0648\u062a var let const<\/h2>\n\n\n\n<p>\u0628\u0647\u200c\u0637\u0648\u0631 \u062e\u0644\u0627\u0635\u0647\u060c \u062a\u0641\u0627\u0648\u062a\u200c\u0647\u0627\u06cc var\u060c let \u0648 const \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0639\u0628\u0627\u0631\u062a\u200c\u0627\u0646\u062f \u0627\u0632:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>var \u062f\u0627\u0631\u0627\u06cc \u062f\u0627\u0645\u0646\u0647 \u0639\u0645\u0644\u06a9\u0631\u062f\u06cc \u0627\u0633\u062a \u0648 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u0622\u0646 \u0631\u0627 \u0645\u062c\u062f\u062f\u0627\u064b \u0627\u0639\u0644\u0627\u0645 \u0648 \u062a\u062e\u0635\u06cc\u0635 \u062f\u0627\u062f.<\/li>\n\n\n\n<li>let \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9 \u0627\u0633\u062a\u060c \u0646\u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u0622\u0646 \u0631\u0627 \u062f\u0631 \u0647\u0645\u0627\u0646 \u0628\u0644\u0648\u06a9 \u0645\u062c\u062f\u062f\u0627\u064b \u0627\u0639\u0644\u0627\u0645 \u06a9\u0631\u062f \u0627\u0645\u0627 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u0622\u0646 \u0631\u0627 \u0645\u062c\u062f\u062f\u0627\u064b \u0627\u062e\u062a\u0635\u0627\u0635 \u062f\u0627\u062f.<\/li>\n\n\n\n<li>const \u062f\u0627\u0631\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9\u06cc \u0627\u0633\u062a\u060c \u0646\u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u062f \u0645\u062c\u062f\u062f\u0627\u064b \u0627\u0639\u0644\u0627\u0645 \u06cc\u0627 \u062a\u062e\u0635\u06cc\u0635 \u062f\u0627\u062f\u0647 \u0634\u0648\u062f. \u06cc\u06a9 \u0645\u062a\u063a\u06cc\u0631 \u0641\u0642\u0637 \u062e\u0648\u0627\u0646\u062f\u0646\u06cc \u0627\u06cc\u062c\u0627\u062f \u0645\u06cc\u200c\u06a9\u0646\u062f.<\/li>\n\n\n\n<li>\u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc var \u0642\u0627\u0628\u0644\u06cc\u062a HIosting \u06a9\u0631\u062f\u0646 \u062f\u0627\u0631\u0646\u062f\u060c \u062f\u0631\u062d\u0627\u0644\u06cc\u200c\u06a9\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc let \u0648 const \u0646\u06cc\u0633\u062a\u0646\u062f.<\/li>\n\n\n\n<li>\u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc var \u0631\u0627 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646 \u0642\u0628\u0644 \u0627\u0632 \u0627\u0639\u0644\u0627\u0645 \u0634\u062f\u0646 (\u06a9\u0647 \u062f\u0631 \u0646\u062a\u06cc\u062c\u0647 \u062a\u0639\u0631\u06cc\u0641 \u0646\u0634\u062f\u0647 \u0627\u0633\u062a) \u062f\u0631 \u062f\u0633\u062a\u0631\u0633 \u0642\u0631\u0627\u0631\u062f\u0627\u062f\u060c \u062f\u0631\u062d\u0627\u0644\u06cc\u200c\u06a9\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc let \u0648 const \u062f\u0627\u0631\u0627\u06cc \u06cc\u06a9 \u0645\u0646\u0637\u0642\u0647 \u0645\u0631\u062f\u0647 \u0632\u0645\u0627\u0646\u06cc \u0647\u0633\u062a\u0646\u062f.<\/li>\n\n\n\n<li>var \u0627\u06af\u0631 \u062e\u0627\u0631\u062c \u0627\u0632 \u06cc\u06a9 \u062a\u0627\u0628\u0639 \u0627\u0639\u0644\u0627\u0646 \u0634\u0648\u062f \u0628\u0647 \u0635\u0648\u0631\u062a \u0633\u0631\u0627\u0633\u0631\u06cc \u062f\u0627\u0631\u0627\u06cc \u062f\u0627\u0645\u0646\u0647 \u0627\u0633\u062a\u060c \u062f\u0631\u062d\u0627\u0644\u06cc\u200c\u06a9\u0647 let \u0648 const \u0646\u06cc\u0633\u062a\u0646\u062f.<\/li>\n\n\n\n<li>let \u0648 const \u0628\u0647 \u062f\u0644\u06cc\u0644 \u0642\u0648\u0627\u0646\u06cc\u0646 \u0645\u062d\u062f\u0648\u062f\u0647 \u062f\u0642\u06cc\u0642\u200c\u062a\u0631 \u0648 \u062e\u0648\u0627\u0646\u0627\u06cc\u06cc \u06a9\u062f \u0628\u0647\u062a\u0631 \u0628\u0631 var \u0627\u0631\u062c\u062d\u06cc\u062a \u062f\u0627\u0631\u0646\u062f.<\/li>\n\n\n\n<li>\u0628\u0631\u0627\u06cc \u0645\u0642\u0627\u062f\u06cc\u0631\u06cc \u06a9\u0647 \u0646\u0628\u0627\u06cc\u062f \u062f\u0648\u0628\u0627\u0631\u0647 \u062a\u062e\u0635\u06cc\u0635 \u062f\u0627\u062f\u0647 \u0634\u0648\u0646\u062f \u0627\u0632 const \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f \u0648 \u0628\u0631\u0627\u06cc \u0645\u0642\u0627\u062f\u06cc\u0631\u06cc \u06a9\u0647 \u0646\u06cc\u0627\u0632 \u0628\u0647 \u062a\u062e\u0635\u06cc\u0635 \u0645\u062c\u062f\u062f \u062f\u0627\u0631\u0646\u062f \u0627\u062c\u0627\u0632\u0647 \u062f\u0647\u06cc\u062f.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter\"><a href=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/f37e3f50.webp\"><img decoding=\"async\" width=\"1024\" height=\"568\" data-src=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/f37e3f50-1024x568.webp\" alt=\"\u062a\u0641\u0627\u0648\u062a var let const\" class=\"wp-image-31417 lazyload\" title=\"\" data-srcset=\"https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/f37e3f50-1024x568.webp 1024w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/f37e3f50-300x166.webp 300w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/f37e3f50-768x426.webp 768w, https:\/\/maktabkhooneh.org\/mag\/wp-content\/uploads\/2023\/07\/f37e3f50.webp 1280w\" data-sizes=\"(max-width: 1024px) 100vw, 1024px\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 1024px; --smush-placeholder-aspect-ratio: 1024\/568;\" \/><\/a><figcaption><\/figcaption><\/figure>\n\n\n\n<p>\u0627\u06cc\u0646 \u062a\u0641\u0627\u0648\u062a\u200c\u0647\u0627 \u0628\u0647 \u062a\u0648\u0633\u0639\u0647\u200c\u062f\u0647\u0646\u062f\u06af\u0627\u0646 \u06a9\u0645\u06a9 \u0645\u06cc\u200c\u06a9\u0646\u062f \u062a\u0627 \u06a9\u062f\u0647\u0627\u06cc \u0642\u0627\u0628\u0644 \u067e\u06cc\u0634\u200c\u0628\u06cc\u0646\u06cc \u0648 \u0642\u0627\u0628\u0644 \u0646\u06af\u0647\u062f\u0627\u0631\u06cc \u0628\u06cc\u0634\u062a\u0631\u06cc \u0631\u0627 \u0628\u0631 \u0627\u0633\u0627\u0633 \u0645\u062d\u062f\u0648\u062f\u0647 \u0645\u062a\u063a\u06cc\u0631 \u062e\u0627\u0635 \u0648 \u0627\u0644\u0632\u0627\u0645\u0627\u062a \u062a\u063a\u06cc\u06cc\u0631\u067e\u0630\u06cc\u0631\u06cc \u062e\u0648\u062f \u0628\u0646\u0648\u06cc\u0633\u0646\u062f.<\/p>\n\n\n\n<p>\u0646\u06a9\u062a\u0647 \u0645\u0647\u0645: Hoisting \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0631\u0641\u062a\u0627\u0631\u06cc \u0627\u0633\u062a \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u0627\u0639\u0644\u0627\u0646\u200c\u0647\u0627\u06cc \u0645\u062a\u063a\u06cc\u0631 \u0648 \u062a\u0627\u0628\u0639 \u062f\u0631 \u0645\u0631\u062d\u0644\u0647 \u06a9\u0627\u0645\u067e\u0627\u06cc\u0644 \u0628\u0647 \u0628\u0627\u0644\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u0645\u0631\u0628\u0648\u0637\u0647 \u062e\u0648\u062f \u0645\u0646\u062a\u0642\u0644 \u0645\u06cc\u200c\u0634\u0648\u0646\u062f. \u0628\u0647 \u0639\u0628\u0627\u0631\u062a \u0633\u0627\u062f\u0647\u060c Hoisting \u0628\u0647 \u0627\u06cc\u0646 \u0645\u0639\u0646\u06cc \u0627\u0633\u062a \u06a9\u0647 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u06cc\u062f \u0627\u0632 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0648 \u062a\u0648\u0627\u0628\u0639 \u0642\u0628\u0644 \u0627\u0632 \u0627\u06cc\u0646\u06a9\u0647 \u062f\u0631 \u06a9\u062f \u062e\u0648\u062f \u062a\u0639\u0631\u06cc\u0641 \u0634\u0648\u0646\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f. \u0628\u0627 \u0627\u06cc\u0646 \u062d\u0627\u0644\u060c \u0641\u0642\u0637 \u0627\u0639\u0644\u0627\u0646\u200c\u0647\u0627 \u0628\u0627\u0644\u0627 \u0645\u06cc\u200c\u0631\u0648\u0646\u062f\u060c \u0646\u0647 \u0645\u0642\u062f\u0627\u0631\u062f\u0647\u06cc \u0627\u0648\u0644\u06cc\u0647 \u06cc\u0627 \u062a\u062e\u0635\u06cc\u0635. \u0645\u0647\u0645 \u0627\u0633\u062a \u06a9\u0647 \u0628\u0631\u0627\u06cc \u062c\u0644\u0648\u06af\u06cc\u0631\u06cc \u0627\u0632 \u0631\u0641\u062a\u0627\u0631\u0647\u0627\u06cc \u063a\u06cc\u0631\u0645\u0646\u062a\u0638\u0631\u0647 Hoisting \u06a9\u0631\u062f\u0646 \u0622\u06af\u0627\u0647 \u0628\u0627\u0634\u06cc\u062f \u0648 \u0628\u0647\u062a\u0631\u06cc\u0646 \u06a9\u0627\u0631 \u0627\u06cc\u0646 \u0627\u0633\u062a \u06a9\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0648 \u062a\u0648\u0627\u0628\u0639 \u0631\u0627 \u0642\u0628\u0644 \u0627\u0632 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 \u0622\u0646\u200c\u0647\u0627 \u0628\u0631\u0627\u06cc \u0628\u0647\u0628\u0648\u062f \u0648\u0636\u0648\u062d \u06a9\u062f \u0627\u0639\u0644\u0627\u0645 \u06a9\u0646\u06cc\u062f.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u0633\u062e\u0646 \u067e\u0627\u06cc\u0627\u0646\u06cc<\/h2>\n\n\n\n<p>\u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9 \u0631\u0627 \u0645\u0639\u0631\u0641\u06cc \u0645\u06cc\u200c\u06a9\u0646\u062f \u06a9\u0647 \u0628\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0627\u062c\u0627\u0632\u0647 \u0645\u06cc\u200c\u062f\u0647\u062f \u062a\u0627 \u0645\u062d\u062f\u0648\u062f\u0647 \u0631\u0627 \u0628\u0647 \u0628\u0644\u0648\u06a9\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u062a\u0639\u0631\u06cc\u0641 \u0634\u062f\u0647\u200c\u0627\u0646\u062f \u0645\u062d\u062f\u0648\u062f \u06a9\u0646\u0646\u062f. \u0627\u06cc\u0646 \u06a9\u0646\u062a\u0631\u0644 \u062f\u0642\u06cc\u0642\u200c\u062a\u0631\u06cc \u0628\u0631 \u0637\u0648\u0644 \u0639\u0645\u0631 \u0645\u062a\u063a\u06cc\u0631 \u0627\u0631\u0627\u0626\u0647 \u0645\u06cc\u200c\u062f\u0647\u062f \u0648 \u062e\u0637\u0631 \u062a\u062f\u0627\u062e\u0644 \u0646\u0627\u0645\u200c\u06af\u0630\u0627\u0631\u06cc \u06cc\u0627 \u062a\u063a\u06cc\u06cc\u0631\u0627\u062a \u0646\u0627\u062e\u0648\u0627\u0633\u062a\u0647 \u0631\u0627 \u06a9\u0627\u0647\u0634 \u0645\u06cc\u200c\u062f\u0647\u062f. \u0646\u06a9\u0627\u062a \u06a9\u0644\u06cc\u062f\u06cc \u06a9\u0647 \u0628\u0627\u06cc\u062f \u062f\u0631 \u0645\u0648\u0631\u062f \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u0628\u0647 \u062e\u0627\u0637\u0631 \u0628\u0633\u067e\u0627\u0631\u06cc\u062f \u0639\u0628\u0627\u0631\u062a\u200c\u0627\u0646\u062f \u0627\u0632:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>let \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0648\u06a9 \u0631\u0627 \u0645\u0639\u0631\u0641\u06cc \u0645\u06cc\u200c\u06a9\u0646\u062f.<\/li>\n\n\n\n<li>let \u062f\u0633\u062a\u0631\u0633\u06cc \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0631\u0627 \u0628\u0647 \u0628\u0644\u0648\u06a9\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u062a\u0639\u0631\u06cc\u0641 \u0634\u062f\u0647\u200c\u0627\u0646\u062f \u0645\u062d\u062f\u0648\u062f \u0645\u06cc\u200c\u06a9\u0646\u062f.<\/li>\n\n\n\n<li>let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0631\u0627 \u062a\u0627 \u0628\u0627\u0644\u0627\u06cc \u0645\u062d\u062f\u0648\u062f\u0647 \u062e\u0648\u062f \u0628\u0627\u0644\u0627 \u0646\u0645\u06cc\u200c\u0628\u0631\u062f.<\/li>\n\n\n\n<li>let \u0627\u0632 \u0627\u0639\u0644\u0627\u0646 \u0645\u062c\u062f\u062f \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u062f\u0631 \u06cc\u06a9 \u0628\u0644\u0648\u06a9 \u062c\u0644\u0648\u06af\u06cc\u0631\u06cc \u0645\u06cc\u200c\u06a9\u0646\u062f.<\/li>\n\n\n\n<li>let \u062f\u0631 Javascript \u0628\u0647\u062a\u0631\u06cc\u0646 \u0634\u06cc\u0648\u0647\u200c\u0647\u0627 \u0631\u0627 \u062a\u0634\u0648\u06cc\u0642 \u0645\u06cc\u200c\u06a9\u0646\u062f \u0648 \u062e\u0648\u0627\u0646\u0627\u06cc\u06cc \u06a9\u062f \u0631\u0627 \u0628\u0647\u0628\u0648\u062f \u0645\u06cc\u200c\u0628\u062e\u0634\u062f.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u0622\u0645\u0648\u0632\u0634 \u0628\u0631\u0646\u0627\u0645\u0647 \u0646\u0648\u06cc\u0633\u06cc \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a<\/h3>\n\n\n\n<p>\u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0645\u0647\u0645\u200c\u062a\u0631\u06cc\u0646 \u0632\u0628\u0627\u0646 \u0628\u0631\u0646\u0627\u0645\u0647 \u0646\u0648\u06cc\u0633\u06cc \u0628\u0631\u0627\u06cc \u062a\u0648\u0633\u0639\u0647 \u0648\u0628 \u0648 \u0637\u0631\u0627\u062d\u06cc \u0633\u0627\u06cc\u062a \u0627\u0633\u062a. \u06cc\u0627\u062f\u06af\u06cc\u0631\u06cc \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0648 \u062d\u0631\u0641\u0647\u200c\u0627\u06cc \u0634\u062f\u0646 \u062f\u0631 \u0622\u0646 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u062f \u0641\u0631\u0635\u062a\u200c\u0647\u0627\u06cc \u0634\u063a\u0644\u06cc \u0628\u06cc\u200c\u067e\u0627\u06cc\u0627\u0646 \u0648 \u0645\u0646\u0627\u0633\u0628\u06cc \u0631\u0627 \u062f\u0631 \u062f\u0633\u062a\u0631\u0633 \u06a9\u0627\u0631\u0628\u0631\u0627\u0646 \u0648 \u0639\u0644\u0627\u0642\u0647\u200c\u0645\u0646\u062f\u0627\u0646 \u0628\u0647 \u0627\u06cc\u0646 \u0632\u0628\u0627\u0646 \u0642\u0631\u0627\u0631 \u062f\u0647\u062f. \u0627\u06af\u0631 \u0628\u0647 \u0641\u06a9\u0631 \u06cc\u0627\u062f\u06af\u06cc\u0631\u06cc \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0647\u0633\u062a\u06cc\u062f \u0648 \u062f\u0648\u0633\u062a \u062f\u0627\u0631\u06cc\u062f \u062f\u0631 \u06a9\u0645\u062a\u0631\u06cc\u0646 \u0632\u0645\u0627\u0646 \u0645\u0645\u06a9\u0646 \u0622\u0646 \u0631\u0627 \u06cc\u0627\u062f \u0628\u06af\u06cc\u0631\u06cc\u062f \u0647\u0645\u200c\u0627\u06a9\u0646\u0648\u0646 \u0628\u0627 \u062b\u0628\u062a\u200c\u0646\u0627\u0645 \u062f\u0631 \u062f\u0648\u0631\u0647\u200c\u0647\u0627\u06cc \u0622\u0645\u0648\u0632\u0634 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0645\u06a9\u062a\u0628 \u062e\u0648\u0646\u0647 \u0645\u0647\u0645\u200c\u062a\u0631\u06cc\u0646 \u0642\u062f\u0645\u200c\u0647\u0627\u06cc \u062e\u0648\u062f \u0631\u0627 \u062f\u0631 \u0627\u06cc\u0646 \u0645\u0633\u06cc\u0631 \u0628\u0631\u062f\u0627\u0631\u06cc\u062f. \u062f\u0631 \u0645\u06a9\u062a\u0628 \u062e\u0648\u0646\u0647 \u0627\u0646\u0648\u0627\u0639 <a href=\"https:\/\/maktabkhooneh.org\/learn\/java-script\/\">\u062f\u0648\u0631\u0647 \u0622\u0645\u0648\u0632\u0634 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a<\/a> \u0628\u0631\u0627\u06cc \u06a9\u0627\u0631\u0628\u0631\u0627\u0646 \u0645\u0628\u062a\u062f\u06cc \u0648 \u067e\u06cc\u0634\u0631\u0641\u062a\u0647 \u0628\u0627 \u0631\u0648\u06cc\u06a9\u0631\u062f\u0647\u0627\u06cc \u0645\u062e\u062a\u0644\u0641\u06cc \u0648\u062c\u0648\u062f \u062f\u0627\u0631\u062f \u06a9\u0647 \u062a\u062e\u0635\u0635 \u0634\u0645\u0627 \u0631\u0627 \u062f\u0631 \u0627\u06cc\u0646 \u0632\u0645\u06cc\u0646\u0647 \u0628\u0647 \u0628\u0647\u062a\u0631\u06cc\u0646 \u0634\u06a9\u0644 \u0645\u0645\u06a9\u0646 \u0627\u0641\u0632\u0627\u06cc\u0634 \u0645\u06cc\u200c\u062f\u0647\u062f.<\/p>\n\n\n\n<p>\u0645\u0646\u0628\u0639 \u0645\u0648\u0631\u062f \u0627\u0633\u062a\u0641\u0627\u062f\u0647: <a href=\"https:\/\/www.javatpoint.com\/javascript-let-keyword\" rel=\"nofollow noopener\" target=\"_blank\">javatpoint<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\u060c \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u00ablet\u00bb \u0628\u0631\u0627\u06cc \u0627\u0639\u0644\u0627\u0645 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627\u06cc\u06cc \u0628\u0627 \u0645\u062d\u062f\u0648\u062f\u0647 \u0628\u0644\u0627\u06a9 (Block Scope) \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0645\u06cc\u200c\u0634\u0648\u062f. \u0627\u06cc\u0646 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u062f\u0631 \u0646\u0633\u062e\u0647 ES2015\/ES6 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0647 \u0647\u0645\u0631\u0627\u0647 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc \u00abconst\u00bb \u0645\u0639\u0631\u0641\u06cc \u0634\u062f. \u062f\u0631 \u0627\u06cc\u0646 \u0645\u0637\u0644\u0628 \u0627\u0632 \u0645\u062c\u0644\u0647 \u0645\u06a9\u062a\u0648\u0628 \u0645\u06cc\u200c\u062e\u0648\u0627\u0647\u06cc\u0645 \u062f\u0631 \u0631\u0627\u0628\u0637\u0647 \u0628\u0627 \u06a9\u0644\u0645\u0647 \u06a9\u0644\u06cc\u062f\u06cc let \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0648 \u0631\u0633\u0627\u0644\u062a \u0622\u0646 \u062a\u0648\u0636\u06cc\u062d\u0627\u062a\u06cc \u06a9\u0627\u0645\u0644 \u0648 \u062c\u0627\u0645\u0639 \u0627\u0631\u0627\u0626\u0647 [&hellip;]<\/p>\n","protected":false},"author":28,"featured_media":31420,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,12],"tags":[],"class_list":["post-31412","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programming-and-it-training","category-java-script-articles"],"_links":{"self":[{"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/posts\/31412","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/comments?post=31412"}],"version-history":[{"count":3,"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/posts\/31412\/revisions"}],"predecessor-version":[{"id":66098,"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/posts\/31412\/revisions\/66098"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/media\/31420"}],"wp:attachment":[{"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/media?parent=31412"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/categories?post=31412"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/maktabkhooneh.org\/mag\/wp-json\/wp\/v2\/tags?post=31412"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}