问题描述

使用xmlhttp访问webservice时，得到的xmlhttp.status=0.而且得不到返回的xml文件

服务器提供了
POST /LoginVerifyWebService/Login.asmx/Login HTTP/1.1
Host: 10.10.10.191
Content-Type: application/x-www-form-urlencoded
Content-Length: length

username=string&password=string&randomString=string

JS代码：
var xmlhttp;
function createXMLHttpRequest(){

    if (window.XMLHttpRequest)
    {// code for IE7+, Firefox, Chrome, Opera, Safari
         xmlhttp=new XMLHttpRequest();
    }
    else
    if(window.ActiveXObject)
    {// code for IE6, IE5
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
    else{
        alert("xmlhttp出错");
    }
 }

  function btn_onclick(){
    createXMLHttpRequest();
    var url="http://10.10.10.191/LoginVerifyWebService/Login.asmx/Login?username=wuhl&password=Wf34566543&randomString=234234";

    xmlhttp.open("GET", url, true);
    xmlhttp.onreadystatechange=Response;
    xmlhttp.send(null);
}
    function Response(){
        alert("a"+xmlhttp.readyState);
        if(xmlhttp.readyState==4){
            alert("xmlhttp.status="+xmlhttp.status);
            if(xmlhttp.status==200){
                alert("c"+xmlhttp.readyState);
                var domObj=xmlhttp.responsetext;
                var messageNodes=domObj.getElementsByTagName("Result");
                alert(messageNodes.firstChild.nodeValue);
            }else{
                alert("请求出错");
            }
        }
    }
</script>