通过js发送请求的几种方法

  var httpAdapter;
    //创建一个httpAdapter对象
    function GethttpAdapterRequest()
    {
        //httpAdapter = window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : new httpAdapterRequest();
         return window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest();
    }
   
    //以Get方式发送请求,默认Content-Type为"text/xml; charset=gb2312"
    this.GetData = function(url)
    {
        httpAdapter = GethttpAdapterRequest();
   httpAdapter.Open("GET",url, false);
   httpAdapter.SetRequestHeader ("Content-Type","text/xml; charset=gb2312");
//   httpAdapter.SetRequestHeader ("SOAPAction","http://tempuri.org/getStr");
   httpAdapter.Send(context);
   return httpAdapter;
    }
   
    //以POST方式发送请求,默认Content-Type为"application/x-www-form-urlencoded"
    this.PostData = function (url,context)
    {
        httpAdapter = GethttpAdapterRequest();
        httpAdapter.Open("POST",url, false);
   httpAdapter.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
//   httpAdapter.SetRequestHeader ("SOAPAction","http://tempuri.org/getStr");
   httpAdapter.Send(context);
   return httpAdapter;
    }
   
   
    this.GetDataInAsync = function (url,callbackMethod)
    {
        httpAdapter = GethttpAdapterRequest();
   httpAdapter.Open("GET",url, true);
   httpAdapter.SetRequestHeader ("Content-Type","text/xml; charset=gb2312");
//   httpAdapter.SetRequestHeader ("SOAPAction","http://tempuri.org/getStr");
   httpAdapter.Send(context);
   httpAdapter.onreadystatechange = callbackMethod;
    }
   
    this.PostDataInAsync = function (url,context,callbackMethod)
    {
        httpAdapter = GethttpAdapterRequest();
        httpAdapter.Open("POST",url, true);
   httpAdapter.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
//   httpAdapter.SetRequestHeader ("SOAPAction","http://tempuri.org/getStr");
   httpAdapter.Send(context);
   httpAdapter.onreadystatechange = callbackMethod;
    }
   
    //获取指定地址的域名
    this.GetHost = function(url)
    {
        var host = "null";
        var ArryHost=new Array();
        if(typeof url == "undefined"|| null == url)
        {
            url = window.location.href;
        }
        var regex = /.*\:\/\/([^\/]*).*/;
        var match = url.match(regex);
        if(typeof match != "undefined" && null != match)
        {
            ArryHost = match[1].split(/:/);
            host =ArryHost[0];
        }
        return host;
    }
   
    //获取当前地址的域名
    this.GetLocalHost=function()
    {
       return GetHost(document.URL);
    }

 

  以前每次写AJAX请求总要写好几个JS函数，包括创建XMLHttpRequest对象、发送请求、成功后的处理函数和失败后的处理函数，下面的JS是把这些东西重构之后参数化的形式，然后放到一个单独的net.js里，后续使用只需引入这个JS，然后新建相应的对象和处理函数即可，可以直接拿来使用

   var net = new Object();
   net.READY_STATE_UNINITIALIZED = 0;
   net.READY_STATE_LOADING = 1;
   net.READY_STATE_LOADED = 2;
   net.READY_STATE_INTERACTIVE = 3;
   net.READY_STATE_COMPLETE = 4;

 

   

   net.ContentLoader = function(url,onload,onerror,method,params,contentType)
   {

    this.req = null;
    this.onload = onload;
    this.onerror = (onerror) ? onerror : this.defaultError;
    this.loadXMLDoc(url,method,params,contentType);
   }

 

   net.ContentLoader.prototype = {
   

   onReadyState: function(){
      
     var req = this.req;
     var ready = req.readyState;
     if(ready == net.READY_STATE_COMPLETE)
     {
        var httpStatus = req.status;
     if(httpStatus == 200 || httpStatus == 0)
         this.onload.call(this);
        else
         this.onerror.call(this);
            }
    },

    defaultError: function(){
          
     alert("error in fetching data!! readyState=="+this.req.readyState+"\n\nstatus="+this.req.status
          +" \n\nheaders"+this.req.getAllResponseHeaders());

    }

 

   }

 

   net.ContentLoader.prototype.loadXMLDoc = function(url,method,params,contentType){

     if(!method)  //如果没有传入method 参数值，则默认为GET
     {
         method = "GET";
     }
     if (!contentType && method=="POST"){
         contentType="application/x-www-form-urlencoded;";
     }
        
     if(window.XMLHttpRequest)
     {
        this.req = new XMLHttpRequest();
      }
     else if(window.ActiveXObject)
     {
        this.req = new ActiveXObject("Microsoft.XMLHTTP");
     }
     if(this.req)
     {

        
       try{
            var loader = this;   
            this.req.onreadystatechange = function(){
                loader.onReadyState.call(loader);
            }
            this.req.open(method,url,true); 
            //POST方法需要设置的属性
            if (contentType){
               this.req.setRequestHeader("Content-Type", contentType);
            } 
            this.req.send(params);
     
       }catch(err)
      { 
          this.onerror.call(this);
      }
    }
 }

 

    代码内容不在做过多解释，如果你对JS面向对象和prototype不太熟悉的话请查阅相关书籍，下面演示如何使用:

1. 把上述内容单独放到一个文件net.js（名称可自己定义)

2. 在要使用的JSP页面上引入这个net.js  即  <script src="net.js"> </script>

3. 发送请求GET方式

   new  net.ContentLoader("http://localhost:8080/CfgWeb/AppLogin.do",getMessage);  

   其中第一个参数是请求的后台程序地址，第二个参数是请求成功后的处理函数（自己定义）

   后面的参数可省略，也可自己添加第三个参数（请求不成功的处理函数）

   function getMessage()

   {

        alert(this.req.responseText);  //简单的输出返回结果的字符串形式

        alert(this.req.responseXML);   //XML形式，后面就根据你的需要解析这个XML了

   }

4. 发送POST请求

   new net.ContentLoader("http://localhost:8080/CfgWeb/AppLogin.do?formAction=autoComplete",getMessage,null,"POST","&userName=wangwei&password=123" );

   function getMessage()

   {

        alert(this.req.responseText);  //简单的输出返回结果的字符串形式

        alert(this.req.responseXML);   //XML形式，后面就根据你的需要解析这个XML了

   }