{"id":1982,"date":"2023-05-04T22:54:54","date_gmt":"2023-05-04T14:54:54","guid":{"rendered":"https:\/\/blog.cauchyschwarz.com\/?p=1982"},"modified":"2023-05-07T20:22:25","modified_gmt":"2023-05-07T12:22:25","slug":"professional-javascript-for-web-developers-3rd-edition-part-5","status":"publish","type":"post","link":"https:\/\/blog.cauchyschwarz.com\/?p=1982","title":{"rendered":"Professional JavaScript for Web Developers, 3rd Edition, Part 5"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_82_2 ez-toc-wrap-right counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-69e0abe98bf94\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-69e0abe98bf94\" checked aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#%E7%AC%AC7%E7%AB%A0_%E5%87%BD%E6%95%B0%E8%A1%A8%E8%BE%BE%E5%BC%8F\" >\u7b2c7\u7ae0 \u51fd\u6570\u8868\u8fbe\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#1%E9%80%92%E5%BD%92\" >1.\u9012\u5f52<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#2%E9%97%AD%E5%8C%85\" >2.\u95ed\u5305<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#1%E9%97%AD%E5%8C%85%E4%B8%8E%E5%8F%98%E9%87%8F\" >1.\u95ed\u5305\u4e0e\u53d8\u91cf<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#2%E5%85%B3%E4%BA%8Ethis%E5%AF%B9%E8%B1%A1\" >2.\u5173\u4e8ethis\u5bf9\u8c61<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#3%E5%86%85%E5%AD%98%E6%B3%84%E9%9C%B2\" >3.\u5185\u5b58\u6cc4\u9732<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#3%E6%A8%A1%E4%BB%BF%E5%9D%97%E7%BA%A7%E4%BD%9C%E7%94%A8%E5%9F%9F\" >3.\u6a21\u4eff\u5757\u7ea7\u4f5c\u7528\u57df<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#4%E7%A7%81%E6%9C%89%E5%8F%98%E9%87%8F\" >4.\u79c1\u6709\u53d8\u91cf<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#1%E9%9D%99%E6%80%81%E7%A7%81%E6%9C%89%E5%8F%98%E9%87%8F\" >1.\u9759\u6001\u79c1\u6709\u53d8\u91cf<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#2%E6%A8%A1%E5%9D%97%E6%A8%A1%E5%BC%8F\" >2.\u6a21\u5757\u6a21\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1982\/#3%E5%A2%9E%E5%BC%BA%E7%9A%84%E6%A8%A1%E5%9D%97%E6%A8%A1%E5%BC%8F\" >3.\u589e\u5f3a\u7684\u6a21\u5757\u6a21\u5f0f<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E7%AC%AC7%E7%AB%A0_%E5%87%BD%E6%95%B0%E8%A1%A8%E8%BE%BE%E5%BC%8F\"><\/span>\u7b2c7\u7ae0 \u51fd\u6570\u8868\u8fbe\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p>\u5b9a\u4e49\u51fd\u6570\u7684\u4e24\u79cd\u65b9\u5f0f\uff0c1.\u51fd\u6570\u58f0\u660e\uff0c2.\u51fd\u6570\u8868\u8fbe\u5f0f\u3002<\/p>\n\n\n\n<p><strong>\u51fd\u6570\u58f0\u660e\u7684\u8bed\u6cd5\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">function functionName(arg0, arg1, arg2) {}<\/code><\/pre>\n\n\n\n<p>\u51fd\u6570\u58f0\u660e\u7684\u4e00\u4e2a\u91cd\u8981\u7279\u5f81\u662f\u51fd\u6570\u58f0\u660e\u63d0\u5347(function declaration hoisting)\uff0c\u5373\u5728\u6267\u884c\u4ee3\u7801\u524d\u4f1a\u5148\u8bfb\u53d6\u51fd\u6570\u58f0\u660e\u3002\u8fd9\u4f7f\u5f97\u53ef\u4ee5\u628a\u51fd\u6570\u58f0\u660e\u653e\u5230\u8c03\u7528\u5b83\u7684\u8bed\u53e5\u540e\u9762\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">sayHi();\nfunction sayHi() {\n    alert(\"Hi!\");\n}<\/code><\/pre>\n\n\n\n<p><strong>\u51fd\u6570\u8868\u8fbe\u5f0f\u7684\u8bed\u6cd5\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">var functionName = function(arg0, arg1, arg2) {}<\/code><\/pre>\n\n\n\n<p>\u5373\u521b\u5efa\u4e00\u4e2a\u533f\u540d\u51fd\u6570(\u6216\u79f0lambda\u51fd\u6570)\uff0c\u5c06\u5176\u8d4b\u7ed9\u4e00\u4e2a\u53d8\u91cf\u3002\u533f\u540d\u51fd\u6570\u7684name\u5c5e\u6027\u662f\u7a7a\u5b57\u7b26\u4e32\u3002<\/p>\n\n\n\n<p>\u4f7f\u7528\u51fd\u6570\u8868\u8fbe\u5f0f\u65f6\uff0c\u5fc5\u987b\u5728\u4f7f\u7528\u524d\u5148\u8d4b\u503c\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">sayHi(); \/\/ error, sayHi\u8fd9\u4e2a\u53d8\u91cf\u8fd8\u4e0d\u5b58\u5728\nvar sayHi = function() {\n    alert(\"Hi!\");\n}<\/code><\/pre>\n\n\n\n<p>\u51fd\u6570\u63d0\u5347\u4e0d\u80fd\u6309\u7167\u4e0b\u9762\u7684\u65b9\u5f0f\u4f7f\u7528\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">    var condition = true;\n    \n    \/\/never do this!\n    if(condition){\n        function sayHi(){\n            alert(\"Hi!\");\n        }\n    } else {\n        function sayHi(){\n            alert(\"Yo!\");\n        }\n    }\n\n    sayHi();\n<\/code><\/pre>\n\n\n\n<p>\u8fd9\u5728ECMAScript\u4e2d\u5c5e\u4e8e\u65e0\u6548\u8bed\u6cd5\u3002<\/p>\n\n\n\n<p>\u60f3\u5b9e\u73b0\u4e0a\u9762\u4ee3\u7801\u7684\u7c7b\u4f3c\u6548\u679c\u53ea\u80fd\u4f7f\u7528\u51fd\u6570\u8868\u8fbe\u5f0f\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">var sayHi;\nif (condition) {\n  sayHi = ...;\n} else {\n  sayHi = ...;\n}<\/code><\/pre>\n\n\n\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1%E9%80%92%E5%BD%92\"><\/span>1.\u9012\u5f52<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p>\u4e0b\u9762\u7684\u9012\u5f52\u4ee3\u7801\u4f1a\u51fa\u9519\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            function factorial(num){\n                if (num &lt;= 1){\n                    return 1;\n                } else {\n                    return num * factorial(num-1);\n                }\n            }\n\n            var anotherFactorial = factorial;\n            factorial = null;\n            alert(anotherFactorial(4));  \/\/error!\n<\/code><\/pre>\n\n\n\n<p>\u56e0\u4e3afactorial\u88ab\u8d4b\u503c\u4e3anull\uff0c\u5bfc\u81f4\u8c03\u7528anotherFactorial\u65f6\u4ee3\u7801\u5bf9factorial\u8fdb\u884c\u8c03\u7528\u51fa\u9519\u3002<\/p>\n\n\n\n<p>\u6b63\u786e\u7684\u505a\u6cd5\u662f\u91cd\u5199factorial\u51fd\u6570\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            function factorial(num){\n                if (num &lt;= 1){\n                    return 1;\n                } else {\n                    return num * arguments.callee(num-1);\n                }\n            }<\/code><\/pre>\n\n\n\n<p>\u4f46\u662f\u5728\u4e25\u683c\u6a21\u5f0f\u4e0b\u65e0\u6cd5\u901a\u8fc7\u811a\u672c\u8bbf\u95eearguments.callee\uff0c\u53ef\u4ee5\u8003\u8651\u4f7f\u7528\u533f\u540d\u51fd\u6570\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            function factorial = (function f(num){\n                if (num &lt;= 1){\n                    return 1;\n                } else {\n                    return num * f(num-1);\n                }\n            });<\/code><\/pre>\n\n\n\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2%E9%97%AD%E5%8C%85\"><\/span>2.\u95ed\u5305<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p>\u95ed\u5305\u662f\u6307\u6709\u6743\u8bbf\u95ee\u53e6\u4e00\u4e2a\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u7684\u53d8\u91cf\u7684\u51fd\u6570\u3002<\/p>\n\n\n\n<p>\u5f53\u67d0\u4e2a\u51fd\u6570\u88ab\u8c03\u7528\u65f6\uff0c\u4f1a\u521b\u5efa\u4e00\u4e2a\u6267\u884c\u73af\u5883(execution context)\u53ca\u76f8\u5e94\u7684\u4f5c\u7528\u57df\u94fe\u3002\u7136\u540e\uff0c\u4f7f\u7528arguments\u548c\u5176\u4ed6\u547d\u540d\u53c2\u6570\u7684\u503c\u6765\u521d\u59cb\u5316\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61(activation object)\u3002\u4f46\u5728\u4f5c\u7528\u57df\u94fe\u4e2d\uff0c\u5916\u90e8\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61\u59cb\u7ec8\u5904\u4e8e\u7b2c\u4e8c\u4f4d\uff0c\u5916\u90e8\u51fd\u6570\u7684\u5916\u90e8\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61\u5904\u4e8e\u7b2c\u4e09\u4f4d\uff0c&#8230;\u76f4\u81f3\u4f5c\u4e3a\u4f5c\u7528\u57df\u94fe\u7ec8\u70b9\u7684\u5168\u5c40\u6267\u884c\u73af\u5883\u3002<\/p>\n\n\n\n<p>\u6362\u53e5\u8bdd\u8bf4\uff1a\u95ed\u5305\u662f\u6307\u6bcf\u4e2a\u51fd\u6570\u5728\u6267\u884c\u65f6\u90fd\u8981\u751f\u6210\u4e00\u4e2a\u6267\u884c\u73af\u5883\uff0c\u8fd9\u4e2a\u6267\u884c\u73af\u5883\u91cc\u6709\u4e00\u4e2a\u4f5c\u7528\u57df\u94fe\uff0c\u4f5c\u7528\u57df\u94fe\u6309\u4f18\u5148\u7ea7\u5305\u542b\u4e86\u7528arguments\u548c\u5176\u4ed6\u547d\u540d\u53c2\u6570\u7684\u503c\u6765\u521d\u59cb\u5316\u7684\u8be5\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61\uff0c\u8be5\u51fd\u6570\u7684\u5916\u90e8\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61\uff0c\u8be5\u51fd\u6570\u7684\u5916\u90e8\u51fd\u6570\u7684\u5916\u90e8\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61\uff0c&#8230;\u6700\u540e\u662f\u4f5c\u4e3a\u4f5c\u7528\u57df\u94fe\u7ec8\u70b9\u7684\u5168\u5c40\u6267\u884c\u73af\u5883\u3002\u8fd9\u4e2a\u4f5c\u7528\u57df\u94fe\u628a\u8be5\u51fd\u6570\u8fd0\u884c\u9700\u8981\u7684\u6240\u6709\u53c2\u6570\u90fd\u5305\u542b\u8fdb\u6765\u4e86\uff0c\u56e0\u6b64\u6210\u4e3a\u95ed\u5305\u3002\u4f46\u662f\u6b63\u56e0\u4e3a\u8981\u5305\u542b\u8fd9\u4e2a\u4f5c\u7528\u57df\u94fe\uff0c\u5bfc\u81f4\u95ed\u5305\u4f1a\u5360\u7528\u66f4\u591a\u7684\u5185\u5b58\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1%E9%97%AD%E5%8C%85%E4%B8%8E%E5%8F%98%E9%87%8F\"><\/span>1.\u95ed\u5305\u4e0e\u53d8\u91cf<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u9700\u8981\u6ce8\u610f\uff0c\u95ed\u5305\u7684\u4f5c\u7528\u57df\u94fe\u4e2d\u5f15\u7528\u7684\u5916\u90e8\u51fd\u6570(\u4ee5\u53ca\u5916\u90e8\u51fd\u6570\u7684\u5916\u90e8\u51fd\u6570\uff0c&#8230;)\u7684\u6d3b\u52a8\u5bf9\u8c61\u4e2d\u7684\u53d8\u91cf\u662f\u5171\u4eab\u7684(\u5373\u5f15\u7528\u7684)\u3002<\/p>\n\n\n\n<p>\u4e0b\u9762\u7684\u51fd\u6570\u53ea\u80fd\u521b\u5efa\u4e00\u4e2a\u5168\u90e8\u8fd4\u8fd810\u7684\u51fd\u6570\u6570\u7ec4\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            function createFunctions(){\n                var result = new Array();\n                \n                for (var i=0; i &lt; 10; i++){\n                    result[i] = function(){\n                        return i;\n                    };\n                }\n                \n                return result;\n            }\n            \n            var funcs = createFunctions();\n            \n            \/\/every function outputs 10\n            for (var i=0; i &lt; funcs.length; i++){\n                document.write(funcs[i]() + \"&lt;br \/>\");\n            }\n<\/code><\/pre>\n\n\n\n<p>\u800c\u4e0b\u9762\u7684\u4ee3\u7801\u4f1a\u8ba9\u6bcf\u4e2a\u51fd\u6570\u8fd4\u56de\u4e0d\u540c\u7684\u503c\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            function createFunctions(){\n                var result = new Array();\n                \n                for (var i=0; i &lt; 10; i++){\n                    result[i] = function(num){\n                        return function(){\n                            return num;\n                        };\n                    }(i);\n                }\n                \n                return result;\n            }\n            \n            var funcs = createFunctions();\n            \n            \/\/every function outputs 10\n            for (var i=0; i &lt; funcs.length; i++){\n                document.write(funcs[i]() + \"&lt;br \/>\");\n            }\n<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2%E5%85%B3%E4%BA%8Ethis%E5%AF%B9%E8%B1%A1\"><\/span>2.\u5173\u4e8ethis\u5bf9\u8c61<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>this\u5bf9\u8c61\u662f\u5728\u8fd0\u884c\u65f6\u57fa\u4e8e\u51fd\u6570\u7684\u6267\u884c\u73af\u5883\u7ed1\u5b9a\u7684\uff1a\u5728\u5168\u5c40\u51fd\u6570\u4e2d\uff0cthis\u7b49\u4e8ewindow\uff0c\u800c\u5f53\u51fd\u6570\u88ab\u4f5c\u4e3a\u67d0\u4e2a\u5bf9\u8c61\u7684\u65b9\u6cd5\u8c03\u7528\u65f6\uff0cthis\u7b49\u4e8e\u8be5\u5bf9\u8c61\u3002<\/p>\n\n\n\n<p>this\u548carguments\u662f\u4e24\u4e2a\u7279\u6b8a\u7684\u53d8\u91cf\uff0c\u6bcf\u4e2a\u51fd\u6570\u5728\u88ab\u8c03\u7528\u65f6\u90fd\u4f1a\u81ea\u52a8\u83b7\u53d6\u8fd9\u4e2a\u53d8\u91cf\u3002\u56e0\u6b64\u5728\u4f5c\u7528\u57df\u94fe\u7684\u5f00\u59cb(\u5373\u8be5\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61)\u5c31\u641c\u7d22\u5230\u4e86\u8fd9\u4e24\u4e2a\u53d8\u91cf\u3002\u65e0\u6cd5\u8bbf\u95ee\u5916\u90e8\u51fd\u6570\u4e2d\u7684this\u53d8\u91cf\uff0c\u9664\u975e\u628a\u5916\u90e8\u51fd\u6570\u4e2d\u7684this\u53d8\u91cf\u4fdd\u5b58\u5230\u5176\u4ed6\u53d8\u91cf\u91cc\u3002<\/p>\n\n\n\n<p>\u4e0b\u9762\u7684\u4ee3\u7801\u4e0d\u80fd\u8bbf\u95ee\u5916\u90e8\u51fd\u6570\u4e2d\u7684this\u53d8\u91cf\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">        var name = \"The Window\";\n        \n        var object = {\n            name : \"My Object\",\n        \n            getNameFunc : function(){\n                return function(){\n                    return this.name;\n                };\n            }\n        };\n        \n        alert(object.getNameFunc()());  \/\/\"The Window\"\n<\/code><\/pre>\n\n\n\n<p>\u4e0b\u9762\u7684\u4ee3\u7801\u901a\u8fc7\u5c06\u5916\u90e8\u51fd\u6570\u7684this\u53d8\u91cf\u4fdd\u5b58\u5230\u65b0\u7684\u53d8\u91cf\u91cc\u5b9e\u73b0\u4e86\u5bf9\u5916\u90e8\u51fd\u6570\u7684this\u53d8\u91cf\u7684\u8bbf\u95ee\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            var name = \"The Window\";\n            \n            var object = {\n                name : \"My Object\",\n            \n                getNameFunc : function(){\n                    var that = this;\n                    return function(){\n                        return that.name;\n                    };\n                }\n            };\n            \n            alert(object.getNameFunc()());  \/\/\"MyObject\"\n<\/code><\/pre>\n\n\n\n<p>\u7406\u89e3\u4e0b\u9762\u51e0\u884c\u51fd\u6570\u8c03\u7528\u7684\u7ed3\u679c\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            var name = \"The Window\";\n            \n            var object = {\n                name : \"My Object\",\n            \n                getName: function(){\n                    return this.name;\n                }\n            };\n            \n            alert(object.getName());     \/\/\"My Object\"\n            alert((object.getName)());   \/\/\"My Object\"\n            alert((object.getName = object.getName)());   \/\/\"The Window\" in non-strict mode\n<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E5%86%85%E5%AD%98%E6%B3%84%E9%9C%B2\"><\/span>3.\u5185\u5b58\u6cc4\u9732<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u95ed\u5305\u4f1a\u5f15\u7528\u5305\u542b\u51fd\u6570\u7684\u6574\u4e2a\u6d3b\u52a8\u5bf9\u8c61\u3002<\/p>\n\n\n\n<p>\u6362\u53e5\u8bdd\u8bf4\uff1a\u95ed\u5305\u4f1a\u5f15\u7528\u5916\u90e8\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61\uff0c\u5bf9\u4e8e\u4e00\u4e9b\u8001\u7248\u672c\u7684IE\u4f1a\u5bfc\u81f4\u5f15\u7528\u8ba1\u6570\u65e0\u6cd5\u53d8\u4e3a0\uff0c\u65e0\u6cd5\u56de\u6536\u5185\u5b58\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E6%A8%A1%E4%BB%BF%E5%9D%97%E7%BA%A7%E4%BD%9C%E7%94%A8%E5%9F%9F\"><\/span>3.\u6a21\u4eff\u5757\u7ea7\u4f5c\u7528\u57df<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p>JavaScript\u6ca1\u6709\u5757\u7ea7\u4f5c\u7528\u57df\u7684\u6982\u5ff5\uff0c\u53d8\u91cf\u4e0d\u662f\u5b9a\u4e49\u5728\u5757\u8bed\u53e5\u4e2d\uff0c\u800c\u662f\u5b58\u5728\u4e8e\u51fd\u6570\u7684\u6d3b\u52a8\u5bf9\u8c61\u4e2d\u7684\u3002\u56e0\u6b64\u53ef\u4ee5\u5229\u7528\u533f\u540d\u51fd\u6570\u6765\u5b9e\u73b0\u5757\u7ea7\u4f5c\u7528\u57df\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">(function(){\n    \/\/\u8fd9\u91cc\u662f\u5757\u7ea7\u4f5c\u7528\u57df\n})();\n\n\n\/\/ \u8bed\u6cd5\u9519\u8bef\uff0c\u51fd\u6570\u58f0\u660e\u540e\u4e0d\u80fd\u518d\u63a5\u7740()\n\/\/ \u9664\u975e\u901a\u8fc7\u4e0a\u9762\u90a3\u6837\u7684\u4ee3\u7801\u52a0()\u5c06\u51fd\u6570\u58f0\u660e\u8f6c\u6362\u4e3a\u51fd\u6570\u8868\u8fbe\u5f0f\nfunction(){\n}();     <\/code><\/pre>\n\n\n\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4%E7%A7%81%E6%9C%89%E5%8F%98%E9%87%8F\"><\/span>4.\u79c1\u6709\u53d8\u91cf<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p>JavaScript\u4e2d\u6ca1\u6709\u79c1\u6709\u6210\u5458\u7684\u6982\u5ff5\uff0c\u6240\u6709\u5bf9\u8c61\u5c5e\u6027\u90fd\u662f\u5171\u6709\u7684\u3002\u4f46\u662f\u6709\u79c1\u6709\u53d8\u91cf\u7684\u6982\u5ff5\uff0c\u5373\u51fd\u6570\u5185\u90e8\u5b9a\u4e49\u7684\u53d8\u91cf(\u5305\u62ec\u51fd\u6570\u7684\u53c2\u6570\u3001\u5c40\u90e8\u53d8\u91cf\u548c\u5728\u51fd\u6570\u5185\u90e8\u5b9a\u4e49\u7684\u5176\u4ed6\u51fd\u6570)\u662f\u4e0d\u80fd\u5728\u5916\u90e8\u8fdb\u884c\u8bbf\u95ee\u7684\u3002<\/p>\n\n\n\n<p>\u4e3a\u4e86\u8bbf\u95ee\u51fd\u6570\u4e2d\u7684\u79c1\u6709\u53d8\u91cf\u548c\u79c1\u6709\u51fd\u6570\uff0c\u65b9\u6cd5\u4e4b\u4e00\u662f\u5728\u6784\u9020\u51fd\u6570\u4e2d\u521b\u5efa\u7279\u6743\u65b9\u6cd5(privileged method)\u3002\u8fd9\u79cd\u65b9\u6cd5\u7684\u7f3a\u70b9\u662f\u6bcf\u4e2a\u5b9e\u4f8b\u90fd\u4f1a\u521b\u5efa\u4e00\u7ec4\u7279\u6743\u65b9\u6cd5\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">            function Person(name){\n            \n                this.getName = function(){\n                    return name;\n                };\n            \n                this.setName = function (value) {\n                    name = value;\n                };\n            }\n            \n            var person = new Person(\"Nicholas\");\n            alert(person.getName());   \/\/\"Nicholas\"\n            person.setName(\"Greg\");\n            alert(person.getName());   \/\/\"Greg\"\n<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1%E9%9D%99%E6%80%81%E7%A7%81%E6%9C%89%E5%8F%98%E9%87%8F\"><\/span>1.\u9759\u6001\u79c1\u6709\u53d8\u91cf<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4e0e\u4e0a\u9762\u7684\u6bcf\u4e2a\u5b9e\u4f8b\u90fd\u6709\u4e00\u7ec4\u79c1\u6709\u53d8\u91cf\u548c\u65b9\u6cd5\u4e0d\u540c\uff0c\u53ef\u4ee5\u901a\u8fc7\u521b\u5efa\u5e76\u8c03\u7528\u4e00\u4e2a\u533f\u540d\u51fd\u6570\u6765\u5b9e\u73b0\u4e00\u4e2a\u79c1\u6709\u4f5c\u7528\u57df\uff0c\u5e76\u5c06\u8be5\u79c1\u6709\u4f5c\u7528\u57df\u7684\u7279\u6743\u65b9\u6cd5\u8d4b\u7ed9\u7c7b\u7684\u539f\u578b\u5bf9\u8c61\u6765\u8ba9\u6240\u6709\u7684\u5b9e\u4f8b\u5171\u4eab\u8be5\u79c1\u6709\u4f5c\u7528\u57df\u91cc\u7684\u53d8\u91cf\u548c\u65b9\u6cd5\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2%E6%A8%A1%E5%9D%97%E6%A8%A1%E5%BC%8F\"><\/span>2.\u6a21\u5757\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4e00\u4e2a\u4e0d\u76f8\u5e72\u7684\u95ee\u9898\uff0c\u4e0b\u9762\u4e09\u6bb5\u4ee3\u7801\u7684\u533a\u522b\u662f\u4ec0\u4e48\uff0c\u4e3a\u4ec0\u4e48\u7b2c2\u4e2a\u4f1a\u62a5\u9519\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"javascript\" class=\"language-javascript\">(function(){\n    \/\/\u8fd9\u91cc\u662f\u5757\u7ea7\u4f5c\u7528\u57df\n})();\n\n\n\/\/ \u8bed\u6cd5\u9519\u8bef\uff0c\u51fd\u6570\u58f0\u660e\u540e\u4e0d\u80fd\u518d\u63a5\u7740()\n\/\/ \u9664\u975e\u901a\u8fc7\u4e0a\u9762\u90a3\u6837\u7684\u4ee3\u7801\u52a0()\u5c06\u51fd\u6570\u58f0\u660e\u8f6c\u6362\u4e3a\u51fd\u6570\u8868\u8fbe\u5f0f\nfunction(){\n}();   \n\n\/\/ \u6b63\u5e38\nvar a = function(){}();<\/code><\/pre>\n\n\n\n<p>\u4e3a\u4e86\u7406\u89e3\u4e0a\u8ff0\u95ee\u9898\uff0c\u5e94\u8be5\u8981\u5148\u7406\u6e05\u51fd\u6570\u8868\u8fbe\u5f0f\u4e0e\u51fd\u6570\u58f0\u660e\u7684\u533a\u522b\uff1a<\/p>\n\n\n\n<p><a href=\"https:\/\/stackoverflow.com\/questions\/336859\/var-functionname-function-vs-function-functionname\">https:\/\/stackoverflow.com\/questions\/336859\/var-functionname-function-vs-function-functionname<\/a><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">var functionOne = function() {\r\n    \/\/ Some code\r\n};\n\nfunction functionTwo() {\r\n    \/\/ Some code\r\n}<\/code><\/pre>\n\n\n\n<p>functionOne\u662f\u51fd\u6570\u8868\u8fbe\u5f0f\uff0c\u8be5\u51fd\u6570\u5b9a\u4e49\u53ea\u6709\u5728\u8fd0\u884c\u5230\u8fd9\u4e00\u884c\u4ee3\u7801\u65f6\u624d\u6709\u5b9a\u4e49\uff0c\u800cfunctionTwo\u662f\u51fd\u6570\u58f0\u660e\uff0c\u5728\u5f00\u59cb\u8fd0\u884c\u6574\u4e2a\u811a\u672c\u65f6\u5c31\u4f1a\u6709\u5b9a\u4e49\u3002<\/p>\n\n\n\n<p>\u56de\u5230\u6700\u4e0a\u9762\u7684\u90a3\u4e09\u6bb5\u4ee3\u7801\uff0c\u4ee5\u4e2a\u4eba\u7406\u89e3\u5176\u4e2d\u7684\u7b2c\u4e8c\u6bb5\u5e94\u8be5\u662f\u4f1a\u6309\u7167\u51fd\u6570\u58f0\u660e\u7684\u65b9\u5f0f\u53bb\u89e3\u6790\u8fd9\u4e2a&#8221;function(){}()\uff1b&#8221;\u4e2d\u7684&#8221;function(){}&#8221;\u8fd9\u5c31\u4f1a\u4ea7\u751f\u7f3a\u5c11\u51fd\u6570\u540d\u7684\u62a5\u9519\u3002\u4f46\u662f\u5982\u679c\u662f\u628a\u8fd9\u4e2a&#8221;function(){}&#8221;\u52a0\u4e0a\u62ec\u53f7\u8868\u8fbe\u5f0f\u6216\u8005\u653e\u5230\u8d4b\u503c\u8bed\u53e5\u91cc\uff0cJavaScript\u5c31\u4f1a\u6309\u7167\u51fd\u6570\u8868\u8fbe\u5f0f\u7684\u89c4\u5219\u53bb\u89e3\u6790\u4ee3\u7801\u5c31\u4e0d\u4f1a\u62a5\u9519\u4e86\u3002<\/p>\n\n\n\n<p>\u56de\u5230\u672c\u8282\u7684\u6a21\u5757\u6a21\u5f0f\uff0c\u5177\u4f53\u6307\u7684\u662f\u901a\u8fc7\u533f\u540d\u51fd\u6570\u8fd4\u56de\u4e00\u4e2a\u5bf9\u8c61\u6765\u5b9e\u73b0\u4e00\u4e2a\u5177\u6709\u79c1\u6709\u53d8\u91cf\u548c\u65b9\u6cd5\u7684\u5355\u4f8b\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3%E5%A2%9E%E5%BC%BA%E7%9A%84%E6%A8%A1%E5%9D%97%E6%A8%A1%E5%BC%8F\"><\/span>3.\u589e\u5f3a\u7684\u6a21\u5757\u6a21\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4e0e\u524d\u9762\u7684\u6a21\u5757\u6a21\u5f0f\u76f8\u6bd4\uff0c\u8fd9\u91cc\u7684\u589e\u5f3a\u6a21\u5757\u6a21\u5f0f\u5176\u5b9e\u5c31\u662f\u5f3a\u884c\u8ba9\u533f\u540d\u51fd\u6570\u8fd4\u56de\u7684\u5bf9\u8c61\u53d8\u6210\u6307\u5b9a\u7c7b\u7684\u5b9e\u4f8b\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7b2c7\u7ae0 \u51fd\u6570\u8868\u8fbe\u5f0f \u5b9a\u4e49\u51fd\u6570\u7684\u4e24\u79cd\u65b9\u5f0f\uff0c1.\u51fd\u6570\u58f0\u660e\uff0c2.\u51fd\u6570\u8868\u8fbe\u5f0f\u3002 \u51fd\u6570\u58f0\u660e\u7684\u8bed\u6cd5\uff1a \u51fd\u6570\u58f0\u660e\u7684\u4e00\u4e2a\u91cd\u8981\u7279\u5f81\u662f\u51fd\u6570\u58f0\u660e\u63d0\u5347(function declaration hoisting)\uff0c\u5373\u5728\u6267\u884c\u4ee3&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10,6],"tags":[166],"class_list":["post-1982","post","type-post","status-publish","format-standard","hentry","category-10","category-6","tag-professionaljavascript"],"_links":{"self":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1982","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1982"}],"version-history":[{"count":18,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1982\/revisions"}],"predecessor-version":[{"id":2020,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1982\/revisions\/2020"}],"wp:attachment":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1982"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1982"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1982"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}