Ajax-Request

function HttpRequest()
{
    this.Request=function(){
        try
        {
            if(window.XMLHttpRequest) request=new XMLHttpRequest();
            if(!request)request=new ActiveXObject("Microsoft.XMLHTTP");
            if(!request)request=new ActiveXObject("Msxml2.XMLHTTP");
     if(!request) alert("不支持");
     return request;
        }
        catch(e)
        {
            alert("不支持XMLHTTPRequest");
        }}
}

   //创建HttpRequest对象
    var request=new HttpRequest().Request();
   //设置监听方法
    request.onreadystatechange=function (){
        if(request.readyState==4)
        {
            if(request.status==200)
            {         
                     //请求成功执行代码       }
            else
            {
                     //请求失败执行代码       }
        }
    }
   //使用Post方法向Url请求信息，异步调用（true）
    request.open("POST",URL+Param,true);
    request.setRequestHeader("Content-Type","text/html;charset=gb2312");
    request.send(null);
    }
    }