{"id":2023,"date":"2025-02-25T22:28:24","date_gmt":"2025-02-25T14:28:24","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2023"},"modified":"2025-02-25T22:28:24","modified_gmt":"2025-02-25T14:28:24","slug":"javascript-%e5%87%bd%e6%95%b0","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/02\/25\/javascript-%e5%87%bd%e6%95%b0\/","title":{"rendered":"JavaScript \u51fd\u6570"},"content":{"rendered":"\n<p>\u5728 JavaScript \u4e2d\uff0c<strong>\u51fd\u6570\uff08Function\uff09<\/strong> \u662f\u4e00\u7ec4\u6267\u884c\u7279\u5b9a\u4efb\u52a1\u6216\u8ba1\u7b97\u7684\u8bed\u53e5\u7684\u96c6\u5408\u3002\u51fd\u6570\u662f JavaScript \u4e2d\u975e\u5e38\u91cd\u8981\u7684\u4e00\u90e8\u5206\uff0c\u5b83\u5141\u8bb8\u4f60\u5c01\u88c5\u4ee3\u7801\uff0c\u590d\u7528\u4ee3\u7801\uff0c\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u7ef4\u62a4\u6027\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. <strong>\u51fd\u6570\u7684\u5b9a\u4e49<\/strong><\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">a. <strong>\u51fd\u6570\u58f0\u660e<\/strong><\/h4>\n\n\n\n<p>\u4f7f\u7528 <code>function<\/code> \u5173\u952e\u5b57\u6765\u58f0\u660e\u4e00\u4e2a\u51fd\u6570\uff0c\u51fd\u6570\u58f0\u660e\u5305\u62ec\u51fd\u6570\u540d\u3001\u53c2\u6570\u5217\u8868\u548c\u51fd\u6570\u4f53\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function greet() {\n  console.log(\"Hello, World!\");\n}\ngreet();  \/\/ \u8f93\u51fa\uff1aHello, World!<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">b. <strong>\u51fd\u6570\u8868\u8fbe\u5f0f<\/strong><\/h4>\n\n\n\n<p>\u51fd\u6570\u8868\u8fbe\u5f0f\u662f\u5c06\u4e00\u4e2a\u51fd\u6570\u8d4b\u503c\u7ed9\u53d8\u91cf\u3002\u5b83\u53ef\u4ee5\u662f\u533f\u540d\u7684\uff08\u6ca1\u6709\u51fd\u6570\u540d\uff09\u6216\u5177\u540d\u7684\uff08\u6709\u51fd\u6570\u540d\uff09\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let greet = function() {\n  console.log(\"Hello, World!\");\n};\ngreet();  \/\/ \u8f93\u51fa\uff1aHello, World!<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">c. <strong>\u7bad\u5934\u51fd\u6570<\/strong>\uff08ES6 \u5f15\u5165\uff09<\/h4>\n\n\n\n<p>\u7bad\u5934\u51fd\u6570\u662f\u51fd\u6570\u8868\u8fbe\u5f0f\u7684\u4e00\u79cd\u7b80\u6d01\u5199\u6cd5\u3002\u5b83\u4e0d\u4f7f\u7528 <code>function<\/code> \u5173\u952e\u5b57\uff0c\u5e76\u4e14\u6ca1\u6709\u81ea\u5df1\u7684 <code>this<\/code>\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let greet = () =&gt; {\n  console.log(\"Hello, World!\");\n};\ngreet();  \/\/ \u8f93\u51fa\uff1aHello, World!<\/code><\/pre>\n\n\n\n<p>\u5982\u679c\u7bad\u5934\u51fd\u6570\u53ea\u6709\u4e00\u4e2a\u53c2\u6570\uff0c\u4e14\u4e0d\u9700\u8981\u5927\u62ec\u53f7\uff0c\u5219\u53ef\u4ee5\u7701\u7565\u62ec\u53f7\u548c\u51fd\u6570\u4f53\u7684\u5927\u62ec\u53f7\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let square = (x) =&gt; x * x;\nconsole.log(square(5));  \/\/ \u8f93\u51fa\uff1a25<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. <strong>\u51fd\u6570\u53c2\u6570<\/strong><\/h3>\n\n\n\n<p>\u51fd\u6570\u53ef\u4ee5\u63a5\u53d7\u53c2\u6570\uff0c\u4e5f\u53eb\u8f93\u5165\u503c\uff0c\u8fd9\u4e9b\u53c2\u6570\u5728\u51fd\u6570\u4f53\u5185\u4f7f\u7528\u3002\u53c2\u6570\u5728\u51fd\u6570\u58f0\u660e\u65f6\u5b9a\u4e49\uff0c\u5e76\u4e14\u53ef\u4ee5\u4f20\u9012\u591a\u4e2a\u53c2\u6570\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function greet(name) {\n  console.log(\"Hello, \" + name);\n}\ngreet(\"Alice\");  \/\/ \u8f93\u51fa\uff1aHello, Alice<\/code><\/pre>\n\n\n\n<p>\u5982\u679c\u51fd\u6570\u8c03\u7528\u65f6\u6ca1\u6709\u4f20\u9012\u67d0\u4e2a\u53c2\u6570\uff0c\u90a3\u4e48\u8be5\u53c2\u6570\u7684\u9ed8\u8ba4\u503c\u662f <code>undefined<\/code>\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function greet(name = \"Guest\") {\n  console.log(\"Hello, \" + name);\n}\ngreet();  \/\/ \u8f93\u51fa\uff1aHello, Guest\ngreet(\"Bob\");  \/\/ \u8f93\u51fa\uff1aHello, Bob<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">\u53c2\u6570\u7684\u4e2a\u6570\uff1a<\/h4>\n\n\n\n<p>JavaScript \u5141\u8bb8\u4f20\u9012\u4efb\u610f\u6570\u91cf\u7684\u53c2\u6570\uff0c\u751a\u81f3\u8d85\u51fa\u51fd\u6570\u58f0\u660e\u4e2d\u7684\u53c2\u6570\u4e2a\u6570\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function sum(a, b) {\n  return a + b;\n}\nconsole.log(sum(1, 2));  \/\/ \u8f93\u51fa\uff1a3\nconsole.log(sum(1, 2, 3, 4));  \/\/ \u8f93\u51fa\uff1a3\uff0c\u56e0\u4e3a\u989d\u5916\u7684\u53c2\u6570\u4f1a\u88ab\u5ffd\u7565<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3. <strong>\u8fd4\u56de\u503c<\/strong><\/h3>\n\n\n\n<p>\u51fd\u6570\u53ef\u4ee5\u8fd4\u56de\u4e00\u4e2a\u503c\u3002<code>return<\/code> \u8bed\u53e5\u7528\u4e8e\u8fd4\u56de\u51fd\u6570\u7684\u7ed3\u679c\uff0c\u51fd\u6570\u6267\u884c\u5230 <code>return<\/code> \u8bed\u53e5\u65f6\u4f1a\u505c\u6b62\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function add(a, b) {\n  return a + b;\n}\nlet result = add(2, 3);\nconsole.log(result);  \/\/ \u8f93\u51fa\uff1a5<\/code><\/pre>\n\n\n\n<p>\u5982\u679c\u6ca1\u6709 <code>return<\/code> \u8bed\u53e5\uff0c\u6216\u8005 <code>return<\/code> \u540e\u6ca1\u6709\u503c\uff0c\u51fd\u6570\u9ed8\u8ba4\u8fd4\u56de <code>undefined<\/code>\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function greet() {\n  console.log(\"Hello!\");\n}\nlet result = greet();  \/\/ \u6ca1\u6709\u8fd4\u56de\u503c\nconsole.log(result);  \/\/ \u8f93\u51fa\uff1aundefined<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">4. <strong>\u51fd\u6570\u7684\u4f5c\u7528\u57df\u548c\u95ed\u5305<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u4f5c\u7528\u57df<\/strong>\uff1a\u6bcf\u4e2a\u51fd\u6570\u90fd\u6709\u81ea\u5df1\u7684\u4f5c\u7528\u57df\u3002\u51fd\u6570\u5185\u90e8\u7684\u53d8\u91cf\u4e0d\u80fd\u5728\u5916\u90e8\u76f4\u63a5\u8bbf\u95ee\uff0c\u800c\u5916\u90e8\u7684\u53d8\u91cf\u4e5f\u4e0d\u80fd\u76f4\u63a5\u5728\u51fd\u6570\u5185\u90e8\u4fee\u6539\u3002<\/li>\n\n\n\n<li><strong>\u95ed\u5305<\/strong>\uff1a\u51fd\u6570\u53ef\u4ee5\u8bbf\u95ee\u5b83\u5916\u90e8\u7684\u53d8\u91cf\uff0c\u5373\u4f7f\u5916\u90e8\u51fd\u6570\u5df2\u7ecf\u6267\u884c\u5b8c\u6bd5\u3002\u95ed\u5305\u53ef\u4ee5\u5e2e\u52a9\u6211\u4eec\u4fdd\u6301\u5bf9\u5916\u90e8\u53d8\u91cf\u7684\u5f15\u7528\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f8b\u5b50\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>function outer() {\n  let outerVar = \"I'm from outer function\";\n  function inner() {\n    console.log(outerVar);  \/\/ \u53ef\u4ee5\u8bbf\u95ee outer() \u7684\u53d8\u91cf\n  }\n  return inner;\n}\nlet closure = outer();\nclosure();  \/\/ \u8f93\u51fa\uff1aI'm from outer function<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">5. <strong>\u51fd\u6570\u7684 <code>this<\/code><\/strong><\/h3>\n\n\n\n<p>\u5728\u51fd\u6570\u4e2d\uff0c<code>this<\/code> \u5173\u952e\u5b57\u6307\u5411\u8c03\u7528\u8be5\u51fd\u6570\u7684\u5bf9\u8c61\u3002\u5bf9\u4e8e\u666e\u901a\u51fd\u6570\uff0c<code>this<\/code> \u6307\u5411\u5168\u5c40\u5bf9\u8c61\uff08\u6d4f\u89c8\u5668\u4e2d\u662f <code>window<\/code>\uff09\u3002\u5bf9\u4e8e\u65b9\u6cd5\u51fd\u6570\uff0c<code>this<\/code> \u6307\u5411\u8c03\u7528\u8be5\u65b9\u6cd5\u7684\u5bf9\u8c61\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f8b\u5b50\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>function greet() {\n  console.log(this);\n}\ngreet();  \/\/ \u8f93\u51fa\uff1awindow (\u6d4f\u89c8\u5668\u73af\u5883\u4e0b)<\/code><\/pre>\n\n\n\n<p>\u5982\u679c\u51fd\u6570\u662f\u4f5c\u4e3a\u5bf9\u8c61\u65b9\u6cd5\u8c03\u7528\u7684\uff0c<code>this<\/code> \u6307\u5411\u8be5\u5bf9\u8c61\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let person = {\n  name: \"Alice\",\n  greet: function() {\n    console.log(\"Hello, \" + this.name);\n  }\n};\nperson.greet();  \/\/ \u8f93\u51fa\uff1aHello, Alice<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">\u7bad\u5934\u51fd\u6570\u4e2d\u7684 <code>this<\/code><\/h4>\n\n\n\n<p>\u7bad\u5934\u51fd\u6570\u4e0d\u4f1a\u521b\u5efa\u81ea\u5df1\u7684 <code>this<\/code>\uff0c\u5b83\u4f1a\u7ee7\u627f\u5916\u90e8\u51fd\u6570\u7684 <code>this<\/code>\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let person = {\n  name: \"Alice\",\n  greet: function() {\n    let innerGreet = () =&gt; {\n      console.log(\"Hello, \" + this.name);\n    };\n    innerGreet();\n  }\n};\nperson.greet();  \/\/ \u8f93\u51fa\uff1aHello, Alice<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">6. <strong>\u51fd\u6570\u7684\u9012\u5f52<\/strong><\/h3>\n\n\n\n<p>\u9012\u5f52\u662f\u6307\u4e00\u4e2a\u51fd\u6570\u76f4\u63a5\u6216\u95f4\u63a5\u5730\u8c03\u7528\u81ea\u8eab\u3002\u9012\u5f52\u51fd\u6570\u5fc5\u987b\u6709\u4e00\u4e2a\u7ec8\u6b62\u6761\u4ef6\uff0c\u5426\u5219\u4f1a\u9020\u6210\u65e0\u9650\u8c03\u7528\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f8b\u5b50\uff1a<\/h4>\n\n\n\n<p>\u8ba1\u7b97\u9636\u4e58\uff08n!\uff09\u7684\u9012\u5f52\u51fd\u6570\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>function factorial(n) {\n  if (n === 0) {  \/\/ \u7ec8\u6b62\u6761\u4ef6\n    return 1;\n  }\n  return n * factorial(n - 1);\n}\nconsole.log(factorial(5));  \/\/ \u8f93\u51fa\uff1a120<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">7. <strong>\u533f\u540d\u51fd\u6570<\/strong><\/h3>\n\n\n\n<p>\u533f\u540d\u51fd\u6570\u662f\u6ca1\u6709\u540d\u79f0\u7684\u51fd\u6570\uff0c\u901a\u5e38\u7528\u4e8e\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u7ed9\u5176\u4ed6\u51fd\u6570\u6216\u4e8b\u4ef6\u5904\u7406\u7a0b\u5e8f\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>setTimeout(function() {\n  console.log(\"Hello after 2 seconds\");\n}, 2000);  \/\/ 2\u79d2\u540e\u8f93\u51fa\uff1aHello after 2 seconds<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">8. <strong>\u51fd\u6570\u8868\u8fbe\u5f0f\u4e0e\u51fd\u6570\u58f0\u660e\u7684\u533a\u522b<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u51fd\u6570\u58f0\u660e<\/strong>\uff1a\u5728\u51fd\u6570\u58f0\u660e\u4e4b\u524d\u5c31\u53ef\u4ee5\u8c03\u7528\uff0c\u56e0\u4e3a JavaScript \u5f15\u64ce\u4f1a\u5c06\u51fd\u6570\u58f0\u660e\u63d0\u5347\u5230\u4ee3\u7801\u9876\u90e8\u3002<\/li>\n\n\n\n<li><strong>\u51fd\u6570\u8868\u8fbe\u5f0f<\/strong>\uff1a\u53ea\u80fd\u5728\u51fd\u6570\u5b9a\u4e49\u540e\u8c03\u7528\uff0c\u56e0\u4e3a\u51fd\u6570\u8868\u8fbe\u5f0f\u662f\u5728\u4ee3\u7801\u6267\u884c\u65f6\u5b9a\u4e49\u7684\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f8b\u5b50\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>myFunc();  \/\/ \u53ef\u4ee5\u6b63\u5e38\u8c03\u7528\uff0c\u56e0\u4e3a\u51fd\u6570\u58f0\u660e\u4f1a\u63d0\u5347\nfunction myFunc() {\n  console.log(\"Function declaration\");\n}\n\nmyFunc2();  \/\/ \u62a5\u9519\uff1amyFunc2 is not a function\uff0c\u56e0\u4e3a\u51fd\u6570\u8868\u8fbe\u5f0f\u4e0d\u63d0\u5347\nvar myFunc2 = function() {\n  console.log(\"Function expression\");\n};<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">9. <strong>\u603b\u7ed3<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u51fd\u6570<\/strong>\u662f JavaScript \u4e2d\u7684\u57fa\u672c\u6784\u5efa\u5757\u4e4b\u4e00\uff0c\u5141\u8bb8\u4f60\u5c01\u88c5\u4e00\u7ec4\u64cd\u4f5c\u5e76\u590d\u7528\u4ee3\u7801\u3002<\/li>\n\n\n\n<li>\u53ef\u4ee5\u4f7f\u7528 <strong>\u51fd\u6570\u58f0\u660e<\/strong>\u3001<strong>\u51fd\u6570\u8868\u8fbe\u5f0f<\/strong> \u6216 <strong>\u7bad\u5934\u51fd\u6570<\/strong> \u5b9a\u4e49\u51fd\u6570\u3002<\/li>\n\n\n\n<li>\u51fd\u6570\u652f\u6301 <strong>\u53c2\u6570<\/strong> \u548c <strong>\u8fd4\u56de\u503c<\/strong>\u3002<\/li>\n\n\n\n<li><code>this<\/code> \u5173\u952e\u5b57\u6307\u5411\u8c03\u7528\u51fd\u6570\u7684\u4e0a\u4e0b\u6587\u5bf9\u8c61\u3002<\/li>\n\n\n\n<li><strong>\u95ed\u5305<\/strong> \u5141\u8bb8\u51fd\u6570\u8bbf\u95ee\u5176\u5916\u90e8\u4f5c\u7528\u57df\u4e2d\u7684\u53d8\u91cf\u3002<\/li>\n\n\n\n<li>\u53ef\u4ee5\u901a\u8fc7\u9012\u5f52\u6765\u5b9e\u73b0\u4e00\u4e9b\u590d\u6742\u7684\u64cd\u4f5c\uff0c\u5982\u8ba1\u7b97\u9636\u4e58\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>\u5728 JavaScript \u4e2d\uff0c\u51fd\u6570\uff08Function\uff09 \u662f\u4e00\u7ec4\u6267\u884c\u7279\u5b9a\u4efb\u52a1\u6216\u8ba1\u7b97\u7684\u8bed\u53e5\u7684\u96c6\u5408\u3002\u51fd\u6570\u662f Java [&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-2023","post","type-post","status-publish","format-standard","hentry","category-javascript"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2023","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=2023"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2023\/revisions"}],"predecessor-version":[{"id":2024,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2023\/revisions\/2024"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2023"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2023"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2023"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}