var xmlhttp;
        function createXMLHttpRequest() //为xmlhttp创建实例
        {
            if(window.ActiveXObject)
            
                xmlhttp=new ActiveXObject('Microsoft.XMLHttp');
                
            else if(window.XMLHttpRequest)
            {
                xmlhttp=new XMLHttpRequest();
            }
        }
        
        function stateRequest(vr1)//状态请求
        {
            if(vr1.length > 5)
            {
            //alert('看来已经执行了stateRequest了');
            createXMLHttpRequest();//引用xmlhttp实例
            xmlhttp.onreadystatechange=handleStateChange;//在请求状态发生改变时调用此方法
            xmlhttp.open("GET","check.aspx?userName="+vr1,true);
            xmlhttp.send(null);
            }
        }
        
        function handleStateChange()
        {
            //alert("看来已经执行了handleStateChange()了");
            var divRet=document.getElementById("ajaxDIV");
            if(xmlhttp.readyState == 4)
            {
                if(xmlhttp.status == 200)
                {
                   var text= GetText();
                   if(text.length != 0)
                   {
                         divRet.innerHTML="<img src=\"images/mootools/ajax_right.gif\" alt=\"right\" />(*^__^*) ok..!";
                         document.getElementById("imgReg").disabled=false; 
                   }
                   else
                   {
                        divRet.innerHTML="<img src=\"images/mootools/ajax_error.gif\" alt=\"error\" />~~~~(>_<)~~~~ no..!";
                        document.getElementById("imgReg").disabled=true; 
                   }
                   
                }
            }
            else
                divRet.innerHTML="<img src=\"images/mootools/ajax-loader.gif\" alt=\"loading\" /><b>loading</b>";
        }
        
        function GetText()
        {
            var results=xmlhttp.responseText;
            //alert(xmlDoc.toString());
            if(results == null)
            {
                //alert("执行到这里了吗");
                return "暂无数据..!";
            }
            else
            {
                return results;
            }
            
        }