javascript全域變數封裝模組實現代碼

最後更新：2018-12-08 來源：互聯網

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下面的代碼是我的測試代碼，注釋很重要：複製代碼代碼如下:/*global window,jQuery,validate_email,masterUI,$,rest*/
/** Enable ECMAScript "strict" operation for this function. See more:
* http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more/
* http://stackoverflow.com/questions/5020479/what-advantages-does-using-functionwindow-document-undefined-windo
* Q1: Why are window and document being fed instead of just being accessed normally?
* A1: Generally to fasten the identifier resolution process, having them as local variables can help (although IMO the performance improvements may be negligible).
* A2: Passing the global object is also a widely used technique on non-browser environments, where you don't have a window identifier at the global scope, e.g.:
* (function (global) {
* //..
* })(this); // this on the global execution context is the global object itself
* A3: Passing window and document allows the script to be more efficiently minified
*
* Q2: Why the heck is undefined being passed in?
* A1: This is made because the undefined global property in ECMAScript 3, is mutable, meaning that someone could change its value affecting your code, for example:
* undefined = true; // mutable
* (function (undefined) {
* alert(typeof undefined); // "undefined", the local identifier
* })(); // <-- no value passed, undefined by default
* If you look carefully undefined is actually not being passed (there's no argument on the function call),
* that's one of the reliable ways to get the undefined value, without using the property window.undefined.
*
*/
(function(window, document, undefined) {
"use strict";
window.test = {
init: function () {
"use strict";
alert("ok");
}
};
})(window, document);// no undefined parameter here to avoid using mutable window.undefined changed by other guy

1.說明，參考了一篇文章和stackoverflow上的一個文章
2.(function(){})() 這種代碼寫在獨立的js檔案裡，當js檔案被html載入的時候，該函數就會執行。實際上建立了windows.text對象。
以後html代碼就可用test.init的形式調用方法。
測試html部分代碼如下：複製代碼代碼如下:[plain] view plaincopyprint?
<head>
<title>AppEngine SDK</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script type="text/javascript" src="../../master/script/third_party/jquery-1.8.0.min.js"></script>
<script type="text/javascript" src="../../master/plugin/jquery-validation-1.9.0/jquery.validate.js"></script>
<script type="text/javascript" src="../../master/plugin/artDialog4.1.6/jquery.artDialog.js"></script>
<script type="text/javascript" src="../../master/script/app/test.js"></script>
<script type="text/javascript">
$(document).ready(function() {
test.init();
})
</script>
</head>

3.Jslint會報兩個問題，一是關於undefined的，沒找到什麼好方法，任它抱怨吧。另一格式最後調用方式要改成：複製代碼代碼如下:[javascript] view plaincopyprint?}(window, document)); }(window, document));

無所謂了，就任由它吧。只要功能正常就行。

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