//1.我们首先创建一个全局变量
    //2.我们在创建一个XmlHttpRequest对象
    var xmlHttp;
    
    function createXmlHttpRequest()
    {
        if(window.XMLHttpRequest)
        {
            xmlHttp=new XMLHttpRequest();
        
            if(xmlHttp.overrideMimeType)
                {
                    xmlHttp.overrideMimeType("text/xml");
                }
        }
        else if(window.ActiveXObject)
        {
            try
            {
                xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");   
            }
            catch(e)
            {
                xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");   
            }
        }
        if(!xmlHttp)
        {
            window.alert("你的浏览器不支持创建XMLhttpRequest对象");
        }
        return xmlHttp;
    }
    

    function ReBtn()
    {

        window.location.reload();
    }
    
    function ValidateCode()
    {
        createXmlHttpRequest();
       
        var url="URL/ValidateCode.aspx?Code="+document.getElementById("TxtCode").value+"&Name="+escape(document.getElementById("TxtName").value)+"&Pwd="+escape(document.getElementById("TxtPwd").value);
       
        xmlHttp.open("GET",url,true);
        
        xmlHttp.onreadystatechange=ValidateResult;
        
        xmlHttp.send(null);
    }
    
    function ValidateResult()
    {
        if(xmlHttp.readyState == 0)
        {
	        document.getElementById("c1").innerHTML = "请求未初始化.....";
        }
        if(xmlHttp.readyState == 1)
        {
	        document.getElementById("c1").innerHTML ="请求已提出.....";
        }
        if(xmlHttp.readyState == 2)
        {
	        document.getElementById("c1").innerHTML ="请求已发送....";
        }
        if(xmlHttp.readyState == 3)
        {
	        document.getElementById("c1").innerHTML ="请求处理中.....";
        }
        if(xmlHttp.readyState == 4)
        {
	        if(xmlHttp.status == 200)
	        {
	            if(xmlHttp.responseText=="2")
                {
                   window.location.href='Main.aspx';
                }
                else if(xmlHttp.responseText=="1")
                {
                    document.getElementById("c1").innerHTML = "用户名或密码错误";
                }
                else 
                {
                   document.getElementById("c1").innerHTML ="验证码输入错误";
                }
	        }
	        else if(xmlHttp.status == 404)
	        {
	            document.getElementById("c1").innerHTML ="此数据未找到......";
	        }
        }
    }