1 var net=new Object();
 2 //编写构造函数
 3 net.AjaxRequest=function(url,onload,onerror,method,params){
 4   this.req=null;
 5   this.onload=onload;
 6   this.onerror=(onerror) ? onerror : this.defaultError;
 7   this.loadDate(url,method,params);
 8 }
 9 //编写用于初始化XMLHttpRequest对象并指定处理函数，最后发送HTTP请求的方法
10 net.AjaxRequest.prototype.loadDate=function(url,method,params){
11   if (!method){
12     method="GET";
13   }
14   if (window.XMLHttpRequest){
15     this.req=new XMLHttpRequest();
16   } else if (window.ActiveXObject){
17     this.req=new ActiveXObject("Microsoft.XMLHTTP");
18   }
19   if (this.req){
20     try{
21       var loader=this;
22       this.req.onreadystatechange=function(){
23         net.AjaxRequest.onReadyState.call(loader);
24       }
25  
26       this.req.open(method,url,true);
27       if(method=="POST"){
28         this.req.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
29       }
30 alert(encodeURI(params));
31      // alert(encodeURI(params));
32       this.req.send(params);
33     }catch (err){
34 alert("hahahhaha");
35       this.onerror.call(this);
36     }
37   }
38 }
39 
40 //重构回调函数
41 net.AjaxRequest.onReadyState=function(){
42   var req=this.req;
43   var ready=req.readyState;
44   if (ready==4){
45     if (req.status==200 ){
46       this.onload.call(this);
47     }else{
48 alert(nihaoaoaoao);
49       this.onerror.call(this);
50     }
51   }
52 }
53 //重构默认的错误处理函籹
54 net.AjaxRequest.prototype.defaultError=function(){
55   alert("error fetching data!"
56     +"\n\nreadyState:"+this.req.readyState
57     +"\nstatus: "+this.req.status
58     +"\nheaders: "+this.req.getAllResponseHeaders());
59 }