{"id":2038,"date":"2025-02-25T22:46:17","date_gmt":"2025-02-25T14:46:17","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2038"},"modified":"2025-02-25T22:46:17","modified_gmt":"2025-02-25T14:46:17","slug":"javascript-if-else-%e8%af%ad%e5%8f%a5","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/02\/25\/javascript-if-else-%e8%af%ad%e5%8f%a5\/","title":{"rendered":"JavaScript\u00a0if&#8230;Else\u00a0\u8bed\u53e5"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\"><strong>\u4e00\u3001JavaScript <code>if...else<\/code> \u8bed\u53e5<\/strong><\/h3>\n\n\n\n<p><code>if...else<\/code> \u8bed\u53e5\u7528\u4e8e\u6839\u636e\u6761\u4ef6\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002\u5728 JavaScript \u4e2d\uff0c<code>if...else<\/code> \u662f\u6700\u5e38\u7528\u7684\u63a7\u5236\u6d41\u8bed\u53e5\u4e4b\u4e00\u3002\u6839\u636e\u6761\u4ef6\u7684\u771f\u5047\uff0c\u7a0b\u5e8f\u4f1a\u51b3\u5b9a\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u8def\u5f84\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">1\u3001<strong>\u57fa\u672c\u8bed\u6cd5<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>if (condition) {\n    \/\/ \u5982\u679c condition \u4e3a true\uff0c\u6267\u884c\u8fd9\u4e2a\u4ee3\u7801\u5757\n} else {\n    \/\/ \u5982\u679c condition \u4e3a false\uff0c\u6267\u884c\u8fd9\u4e2a\u4ee3\u7801\u5757\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">2\u3001<strong>\u793a\u4f8b\uff1a\u57fa\u672c\u7684 <code>if...else<\/code> \u8bed\u53e5<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let age = 20;\n\nif (age &gt;= 18) {\n    console.log(\"\u4f60\u662f\u6210\u5e74\u4eba\uff01\");\n} else {\n    console.log(\"\u4f60\u662f\u672a\u6210\u5e74\u4eba\uff01\");\n}<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c<code>if<\/code> \u8bed\u53e5\u68c0\u67e5 <code>age<\/code> \u662f\u5426\u5927\u4e8e\u6216\u7b49\u4e8e 18\uff0c\u5982\u679c\u4e3a <code>true<\/code>\uff0c\u6267\u884c <code>console.log(\"\u4f60\u662f\u6210\u5e74\u4eba\uff01\")<\/code>\uff1b\u5982\u679c\u4e3a <code>false<\/code>\uff0c\u5219\u6267\u884c <code>console.log(\"\u4f60\u662f\u672a\u6210\u5e74\u4eba\uff01\")<\/code>\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e8c\u3001<strong><code>if...else if...else<\/code> \u8bed\u53e5<\/strong><\/h3>\n\n\n\n<p>\u6709\u65f6\u9700\u8981\u591a\u4e2a\u6761\u4ef6\u5224\u65ad\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>else if<\/code> \u6765\u5224\u65ad\u591a\u4e2a\u4e0d\u540c\u7684\u6761\u4ef6\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">1\u3001<strong>\u8bed\u6cd5<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>if (condition1) {\n    \/\/ \u5982\u679c condition1 \u4e3a true\uff0c\u6267\u884c\u8fd9\u4e2a\u4ee3\u7801\u5757\n} else if (condition2) {\n    \/\/ \u5982\u679c condition2 \u4e3a true\uff0c\u6267\u884c\u8fd9\u4e2a\u4ee3\u7801\u5757\n} else {\n    \/\/ \u5982\u679c\u4ee5\u4e0a\u6761\u4ef6\u90fd\u4e0d\u6ee1\u8db3\uff0c\u6267\u884c\u8fd9\u4e2a\u4ee3\u7801\u5757\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">2\u3001<strong>\u793a\u4f8b\uff1a\u591a\u4e2a\u6761\u4ef6\u7684 <code>if...else if...else<\/code><\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let score = 85;\n\nif (score &gt;= 90) {\n    console.log(\"\u6210\u7ee9\u4f18\u79c0\");\n} else if (score &gt;= 75) {\n    console.log(\"\u6210\u7ee9\u826f\u597d\");\n} else if (score &gt;= 60) {\n    console.log(\"\u6210\u7ee9\u5408\u683c\");\n} else {\n    console.log(\"\u6210\u7ee9\u4e0d\u53ca\u683c\");\n}<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u6839\u636e <code>score<\/code> \u7684\u503c\u6765\u8f93\u51fa\u4e0d\u540c\u7684\u7ed3\u679c\u3002\u5982\u679c <code>score<\/code> \u5927\u4e8e\u6216\u7b49\u4e8e 90\uff0c\u8f93\u51fa\u201c\u6210\u7ee9\u4f18\u79c0\u201d\uff1b\u5982\u679c\u5728 75 \u5230 89 \u4e4b\u95f4\uff0c\u8f93\u51fa\u201c\u6210\u7ee9\u826f\u597d\u201d\uff1b\u5982\u679c\u5728 60 \u5230 74 \u4e4b\u95f4\uff0c\u8f93\u51fa\u201c\u6210\u7ee9\u5408\u683c\u201d\uff1b\u5426\u5219\u8f93\u51fa\u201c\u6210\u7ee9\u4e0d\u53ca\u683c\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong><code>\u4e09\u3001if<\/code> \u8bed\u53e5\u7684\u5d4c\u5957\uff08Nested <code>if<\/code>\uff09<\/strong><\/h3>\n\n\n\n<p>\u4f60\u53ef\u4ee5\u5c06\u4e00\u4e2a <code>if<\/code> \u8bed\u53e5\u5d4c\u5957\u5728\u53e6\u4e00\u4e2a <code>if<\/code> \u8bed\u53e5\u4e2d\uff0c\u8fdb\u884c\u66f4\u590d\u6742\u7684\u6761\u4ef6\u5224\u65ad\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>\u793a\u4f8b\uff1a\u5d4c\u5957\u7684 <code>if<\/code> \u8bed\u53e5<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let age = 20;\nlet hasPermission = true;\n\nif (age &gt;= 18) {\n    if (hasPermission) {\n        console.log(\"\u53ef\u4ee5\u8bbf\u95ee\u8be5\u9875\u9762\");\n    } else {\n        console.log(\"\u6ca1\u6709\u6743\u9650\u8bbf\u95ee\u8be5\u9875\u9762\");\n    }\n} else {\n    console.log(\"\u672a\u6ee118\u5c81\uff0c\u4e0d\u80fd\u8bbf\u95ee\u8be5\u9875\u9762\");\n}<\/code><\/pre>\n\n\n\n<p>\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u9996\u5148\u5224\u65ad <code>age<\/code> \u662f\u5426\u5927\u4e8e\u6216\u7b49\u4e8e 18\uff0c\u5982\u679c\u662f\uff0c\u518d\u8fdb\u4e00\u6b65\u5224\u65ad <code>hasPermission<\/code> \u662f\u5426\u4e3a <code>true<\/code>\u3002\u8fd9\u79cd\u5d4c\u5957\u7684\u5224\u65ad\u53ef\u4ee5\u5904\u7406\u66f4\u590d\u6742\u7684\u4e1a\u52a1\u903b\u8f91\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u56db\u3001<strong><code>if<\/code> \u8bed\u53e5\u7684\u7b80\u5199\u65b9\u5f0f<\/strong><\/h3>\n\n\n\n<p>\u5728 JavaScript \u4e2d\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528 <strong>\u4e09\u5143\u8fd0\u7b97\u7b26<\/strong> \u6765\u7b80\u5199 <code>if...else<\/code> \u8bed\u53e5\uff0c\u5c24\u5176\u9002\u7528\u4e8e\u6761\u4ef6\u5224\u65ad\u7ed3\u679c\u53ea\u6709\u4e24\u4e2a\u60c5\u51b5\u7684\u60c5\u51b5\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>\u4e09\u5143\u8fd0\u7b97\u7b26\u7b80\u5199 <code>if...else<\/code><\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let age = 20;\nlet result = (age &gt;= 18) ? \"\u6210\u5e74\u4eba\" : \"\u672a\u6210\u5e74\u4eba\";\nconsole.log(result);  \/\/ \u8f93\u51fa: \u6210\u5e74\u4eba<\/code><\/pre>\n\n\n\n<p>\u8fd9\u6bb5\u4ee3\u7801\u4f7f\u7528\u4e09\u5143\u8fd0\u7b97\u7b26\u66ff\u4ee3\u4e86 <code>if...else<\/code> \u8bed\u53e5\u3002\u5b83\u68c0\u67e5 <code>age<\/code> \u662f\u5426\u5927\u4e8e\u6216\u7b49\u4e8e 18\uff0c\u5982\u679c\u662f\uff0c<code>result<\/code> \u4e3a <code>\"\u6210\u5e74\u4eba\"<\/code>\uff0c\u5426\u5219\u4e3a <code>\"\u672a\u6210\u5e74\u4eba\"<\/code>\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>\u603b\u7ed3<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>if...else<\/code> \u7528\u4e8e\u6839\u636e\u6761\u4ef6\u5224\u65ad\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002<\/li>\n\n\n\n<li><code>else if<\/code> \u5141\u8bb8\u4f60\u5728 <code>if<\/code> \u6761\u4ef6\u4e0d\u6ee1\u8db3\u65f6\uff0c\u6dfb\u52a0\u591a\u4e2a\u989d\u5916\u7684\u6761\u4ef6\u5224\u65ad\u3002<\/li>\n\n\n\n<li>\u5d4c\u5957\u7684 <code>if<\/code> \u8bed\u53e5\u5141\u8bb8\u4f60\u8fdb\u884c\u66f4\u590d\u6742\u7684\u6761\u4ef6\u5224\u65ad\u3002<\/li>\n\n\n\n<li>\u53ef\u4ee5\u4f7f\u7528\u4e09\u5143\u8fd0\u7b97\u7b26\u6765\u7b80\u5316\u7b80\u5355\u7684\u6761\u4ef6\u5224\u65ad\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u4e9b\u8bed\u53e5\u662f JavaScript \u4e2d\u5e38\u89c1\u7684\u63a7\u5236\u6d41\u8bed\u53e5\uff0c\u53ef\u4ee5\u5e2e\u52a9\u4f60\u6839\u636e\u4e0d\u540c\u7684\u6761\u4ef6\u6267\u884c\u4e0d\u540c\u7684\u64cd\u4f5c\u3002\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00\u3001JavaScript if&#8230;else \u8bed\u53e5 if&#8230;else \u8bed\u53e5\u7528\u4e8e\u6839\u636e\u6761\u4ef6\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002\u5728  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[],"class_list":["post-2038","post","type-post","status-publish","format-standard","hentry","category-javascript"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2038","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=2038"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2038\/revisions"}],"predecessor-version":[{"id":2039,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2038\/revisions\/2039"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2038"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2038"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2038"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}