ajax代码

        function send_request(flag)
        {
            //创建XMLHttpRequest;
            http_request = false;
            if(window.XMLHttpRequest)
            {
                //　非IE　浏览器
                http_request = new XMLHttpRequest();
            }
            else if(window.ActiveXObject)
            {
                //IE
                try
                {
                    http_request = new ActiveXObject("Msxml2.XMLHTTP");//较新版本的IE
                }catch(e)
                {
                    try
                    {
                        http_request = new ActiveXOBject("Microsoft.XMLHTTP");//旧版本IE
                    }catch(e){}                   
                }
            }
            else
            {
                window.alert("不能创建　XMLHttpRequest对象，无法应用Ajax");
                return false;
            }
            //指定回调函数
            if(flag == "func")
            {
                 http_request.onreadystatechange = func;
                  //创建HTTP请求
                 http_request.open("get","Handler.ashx?flag=func");            
            }        
          
            //发送上面创建的HTTP请求
            http_request.send(null); 
        }
        function func()
        { 
            if(http_request.readyState == 4)//发送成功
            {
                if(http_request.status == 200)//交易成功
                { 
                    .........
                }
            }
        }