javascript全局变量封装模块实现代码

  下面的代码是我的测试代码,注释很重要:

  

复制代码 代码如下:

  /*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.说明,参考了一篇文章和stackoverflow上的一个帖子

  2.(function(){})() 这种代码写在独立的js文件里,当js文件被html加载的时候,该函数就会执行。实际上创建了windows.text对象。

  以后html代码就可用test.init的形式调用方法。

  测试html部分代码如下:

  

复制代码 代码如下:

  [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会报两个问题,一是关于undefined的,没找到什么好方法,任它抱怨吧。另一格式最后调用方式要改成:

  

复制代码 代码如下:

  [javascript] view plaincopyprint?}(window, document)); }(window, document));

  无所谓了,就任由它吧。只要功能正常就行。