{"id":2040,"date":"2025-02-25T22:48:26","date_gmt":"2025-02-25T14:48:26","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2040"},"modified":"2025-02-25T22:48:26","modified_gmt":"2025-02-25T14:48:26","slug":"javascript-switch-%e8%af%ad%e5%8f%a5","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/02\/25\/javascript-switch-%e8%af%ad%e5%8f%a5\/","title":{"rendered":"JavaScript\u00a0switch\u00a0\u8bed\u53e5"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\"><strong>JavaScript <code>switch<\/code> \u8bed\u53e5<\/strong><\/h3>\n\n\n\n<p><code>switch<\/code> \u8bed\u53e5\u662f\u53e6\u4e00\u4e2a\u7528\u4e8e\u591a\u6761\u4ef6\u5224\u65ad\u7684\u63a7\u5236\u6d41\u8bed\u53e5\uff0c\u5b83\u7684\u4f5c\u7528\u662f\u6839\u636e\u4e00\u4e2a\u53d8\u91cf\u7684\u503c\u6765\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002\u76f8\u6bd4 <code>if...else if...else<\/code> \u8bed\u53e5\uff0c<code>switch<\/code> \u8bed\u53e5\u5bf9\u4e8e\u591a\u4e2a\u4e0d\u540c\u6761\u4ef6\u7684\u5224\u65ad\u6765\u8bf4\u66f4\u7b80\u6d01\u3001\u66f4\u6613\u8bfb\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>\u57fa\u672c\u8bed\u6cd5<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>switch (expression) {\n    case value1:\n        \/\/ \u5982\u679c expression \u7684\u503c\u4e0e value1 \u5339\u914d\uff0c\u6267\u884c\u8fd9\u90e8\u5206\u4ee3\u7801\n        break;\n    case value2:\n        \/\/ \u5982\u679c expression \u7684\u503c\u4e0e value2 \u5339\u914d\uff0c\u6267\u884c\u8fd9\u90e8\u5206\u4ee3\u7801\n        break;\n    case value3:\n        \/\/ \u5982\u679c expression \u7684\u503c\u4e0e value3 \u5339\u914d\uff0c\u6267\u884c\u8fd9\u90e8\u5206\u4ee3\u7801\n        break;\n    default:\n        \/\/ \u5982\u679c expression \u7684\u503c\u4e0e\u6240\u6709 case \u90fd\u4e0d\u5339\u914d\uff0c\u6267\u884c\u8fd9\u90e8\u5206\u4ee3\u7801\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>\u793a\u4f8b\uff1a\u57fa\u672c\u7684 <code>switch<\/code> \u8bed\u53e5<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let day = 2;\nswitch (day) {\n    case 1:\n        console.log(\"\u4eca\u5929\u662f\u661f\u671f\u4e00\");\n        break;\n    case 2:\n        console.log(\"\u4eca\u5929\u662f\u661f\u671f\u4e8c\");\n        break;\n    case 3:\n        console.log(\"\u4eca\u5929\u662f\u661f\u671f\u4e09\");\n        break;\n    default:\n        console.log(\"\u65e0\u6548\u7684\u65e5\u671f\");\n}<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c<code>switch<\/code> \u6839\u636e <code>day<\/code> \u7684\u503c\u6765\u5339\u914d\u5bf9\u5e94\u7684 <code>case<\/code>\u3002\u5982\u679c <code>day<\/code> \u7684\u503c\u4e3a 2\uff0c\u5219\u8f93\u51fa\u201c\u4eca\u5929\u662f\u661f\u671f\u4e8c\u201d\u3002\u5982\u679c\u6ca1\u6709\u4efb\u4f55 <code>case<\/code> \u5339\u914d <code>day<\/code> \u7684\u503c\uff0c\u5219\u6267\u884c <code>default<\/code> \u90e8\u5206\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><code>break<\/code> \u8bed\u53e5<\/strong><\/h4>\n\n\n\n<p><code>break<\/code> \u8bed\u53e5\u7528\u4e8e\u5728 <code>case<\/code> \u5339\u914d\u540e\u9000\u51fa <code>switch<\/code> \u8bed\u53e5\u3002\u5982\u679c\u6ca1\u6709 <code>break<\/code>\uff0c\u4f1a\u7ee7\u7eed\u6267\u884c\u4e0b\u4e00\u4e2a <code>case<\/code>\uff0c\u8fd9\u5c31\u662f\u6240\u8c13\u7684\u201c\u7a7f\u900f\uff08fall through\uff09\u201d\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let fruit = \"apple\";\n\nswitch (fruit) {\n    case \"apple\":\n        console.log(\"\u8fd9\u662f\u82f9\u679c\");\n        break;\n    case \"banana\":\n        console.log(\"\u8fd9\u662f\u9999\u8549\");\n        break;\n    case \"orange\":\n        console.log(\"\u8fd9\u662f\u6a59\u5b50\");\n        break;\n    default:\n        console.log(\"\u672a\u77e5\u7684\u6c34\u679c\");\n}<\/code><\/pre>\n\n\n\n<p>\u5982\u679c <code>fruit<\/code> \u662f <code>\"apple\"<\/code>\uff0c\u4f1a\u8f93\u51fa <code>\"\u8fd9\u662f\u82f9\u679c\"<\/code> \u5e76\u505c\u6b62\u7ee7\u7eed\u6267\u884c\uff1b\u5982\u679c\u6ca1\u6709 <code>break<\/code>\uff0c<code>switch<\/code> \u4f1a\u7ee7\u7eed\u68c0\u67e5\u5176\u4ed6\u7684 <code>case<\/code>\uff0c\u76f4\u5230\u627e\u5230\u5339\u914d\u7684 <code>case<\/code> \u6216\u5230\u8fbe <code>default<\/code>\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>\u6ca1\u6709 <code>break<\/code> \u7684\u7a7f\u900f\u884c\u4e3a<\/strong><\/h4>\n\n\n\n<p>\u5982\u679c\u4e0d\u4f7f\u7528 <code>break<\/code>\uff0c<code>switch<\/code> \u4f1a\u7ee7\u7eed\u6267\u884c\u4e0b\u4e00\u4e2a <code>case<\/code> \u4ee3\u7801\u5757\uff0c\u76f4\u5230\u9047\u5230 <code>break<\/code> \u6216\u8005\u7ed3\u675f <code>switch<\/code> \u8bed\u53e5\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let color = \"red\";\n\nswitch (color) {\n    case \"red\":\n        console.log(\"\u7ea2\u8272\");\n    case \"green\":\n        console.log(\"\u7eff\u8272\");\n    case \"blue\":\n        console.log(\"\u84dd\u8272\");\n    default:\n        console.log(\"\u672a\u77e5\u989c\u8272\");\n}<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\u7ea2\u8272\n\u7eff\u8272\n\u84dd\u8272\n\u672a\u77e5\u989c\u8272<\/code><\/pre>\n\n\n\n<p>\u8fd9\u91cc\uff0c<code>color<\/code> \u7684\u503c\u662f <code>\"red\"<\/code>\uff0c\u6240\u4ee5 <code>console.log(\"\u7ea2\u8272\")<\/code> \u4f1a\u9996\u5148\u6267\u884c\uff0c\u4f46\u7531\u4e8e\u6ca1\u6709 <code>break<\/code>\uff0c\u5b83\u4f1a\u7ee7\u7eed\u6267\u884c\u540e\u9762\u7684 <code>case<\/code> \u4ee3\u7801\u5757\uff0c\u76f4\u5230\u6700\u540e\u6267\u884c <code>default<\/code>\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><code>switch<\/code> \u4e0e\u6570\u636e\u7c7b\u578b<\/strong><\/h4>\n\n\n\n<p><code>switch<\/code> \u8bed\u53e5\u7684\u6bd4\u8f83\u662f <strong>\u4e25\u683c\u6bd4\u8f83<\/strong>\uff08\u5373 <code>===<\/code>\uff09\uff0c\u8fd9\u610f\u5473\u7740 <code>switch<\/code> \u8bed\u53e5\u4f1a\u8003\u8651\u6570\u636e\u7c7b\u578b\uff0c\u6240\u4ee5\u53ea\u6709 <code>expression<\/code> \u548c <code>case<\/code> \u7684\u503c <strong>\u7c7b\u578b\u548c\u6570\u503c<\/strong>\u90fd\u76f8\u540c\uff0c\u624d\u4f1a\u5339\u914d\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let x = 1;\nswitch (x) {\n    case \"1\":  \/\/ \u5b57\u7b26\u4e32\u7c7b\u578b\n        console.log(\"\u8fd9\u662f\u5b57\u7b26\u4e32 1\");\n        break;\n    case 1:    \/\/ \u6570\u5b57\u7c7b\u578b\n        console.log(\"\u8fd9\u662f\u6570\u5b57 1\");\n        break;\n    default:\n        console.log(\"\u6ca1\u6709\u5339\u914d\u7684\u503c\");\n}<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\u8fd9\u662f\u6570\u5b57 1<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u867d\u7136 <code>x<\/code> \u7684\u503c\u662f <code>1<\/code>\uff0c\u4f46\u662f <code>switch<\/code> \u8bed\u53e5\u4f1a\u4e25\u683c\u68c0\u67e5\u7c7b\u578b\u3002<code>case \"1\"<\/code> \u662f\u5b57\u7b26\u4e32\uff0c\u800c <code>x<\/code> \u662f\u6570\u5b57\uff0c\u56e0\u6b64\u6ca1\u6709\u5339\u914d <code>case \"1\"<\/code>\uff0c\u6700\u7ec8\u5339\u914d\u7684\u662f <code>case 1<\/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>switch<\/code> \u8bed\u53e5\u7528\u4e8e\u6839\u636e\u4e00\u4e2a\u53d8\u91cf\u7684\u503c\u6765\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002<\/li>\n\n\n\n<li>\u5b83\u6bd4\u591a\u4e2a <code>if...else if...else<\/code> \u8bed\u53e5\u66f4\u7b80\u6d01\uff0c\u5c24\u5176\u9002\u5408\u6761\u4ef6\u5206\u652f\u8f83\u591a\u7684\u60c5\u51b5\u3002<\/li>\n\n\n\n<li><code>case<\/code> \u540e\u7684\u503c\u4f1a\u4e25\u683c\u6bd4\u8f83\uff08\u5373 <code>===<\/code>\uff09\uff0c\u56e0\u6b64\u6570\u636e\u7c7b\u578b\u5fc5\u987b\u4e00\u81f4\u624d\u80fd\u5339\u914d\u3002<\/li>\n\n\n\n<li><code>break<\/code> \u7528\u4e8e\u9000\u51fa <code>switch<\/code> \u8bed\u53e5\uff0c\u5426\u5219\u4f1a\u7ee7\u7eed\u6267\u884c\u540e\u7eed\u7684 <code>case<\/code>\uff0c\u76f4\u5230\u7ed3\u675f\u6216\u9047\u5230 <code>break<\/code>\u3002<\/li>\n\n\n\n<li><code>default<\/code> \u7528\u4e8e\u5904\u7406\u6ca1\u6709\u5339\u914d\u5230\u4efb\u4f55 <code>case<\/code> \u65f6\u7684\u9ed8\u8ba4\u60c5\u51b5\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>JavaScript switch \u8bed\u53e5 switch \u8bed\u53e5\u662f\u53e6\u4e00\u4e2a\u7528\u4e8e\u591a\u6761\u4ef6\u5224\u65ad\u7684\u63a7\u5236\u6d41\u8bed\u53e5\uff0c\u5b83\u7684\u4f5c\u7528\u662f\u6839\u636e [&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-2040","post","type-post","status-publish","format-standard","hentry","category-javascript"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2040","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=2040"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2040\/revisions"}],"predecessor-version":[{"id":2041,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2040\/revisions\/2041"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2040"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2040"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2040"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}