Ajax类应用示例代码

1. /*********************************************************************************************
2.  Ajax类应用示例代码:
3.  new Ajax({
4.      url: 'readMessageList.action',
5.      onComplete: function(data){document.getElementById('message_div').innerHTML += data;}
6.  }).doRequest();
7. **********************************************************************************************/
9. Ajax = function(config)
10. {
11.     this._xmlHttpRequest = null;
12.     this._userConfig = config;
13.     this._config = {
14.         method: 'get',      // get||post|| ...
15.         async: true,
16.         returnDataFormat: 'jsCode',     // jsCode||string||xml
17.         url: null,
18.         onComplete: function(data){}
19.     };
20.     this._init = function()
21.     {
22.         if (window.XMLHttpRequest) {
23.             this._xmlHttpRequest = window.XMLHttpRequest;
24.         }
25.         else {
26.             this._xmlHttpRequest = new ActiveXObject('Microsoft.XMLHTTP');
27.         }
28.         
29.     };
30.     
31.     this.doRequest = function()
32.     {
33.         var instance = this;
34.         if (!this._xmlHttpRequest) {
35.             this._init();
36.         }
37.         if (this._userConfig) {
38.             for (var key in this._userConfig) {
39.                 this._config[key] = this._userConfig[key];
40.             }
41.         }
42.         this._xmlHttpRequest.open(this._config.method, this._config.url, this._config.async);
43.         this._xmlHttpRequest.onreadystatechange = function()
44.         {
45.             if (instance._xmlHttpRequest.readyState == 4){
46.                 if (instance._xmlHttpRequest.status == 200){
47.                     var responseText = instance._xmlHttpRequest.responseText;
48.                     if (instance._config.returnDataFormat == 'jsCode') {
49.                         instance._config.onComplete(eval('(' + responseText + ')'));
50.                     }
51.                     else if (instance._config.returnDataFormat == 'string') {
52.                         instance._config.onComplete(responseText);
53.                     }
54.                     else if (instance._config.returnDataFormat == 'xml'){
55.                         instance._config.onComplete(instance._xmlHttpRequest.responseXml);
56.                     }
57.                 }
58.             }
59.             
60.         };
61.         instance._xmlHttpRequest.send(null);
62.     }
63. }