JS调用WebService 无刷新获得在线消息

调用WebService传回的XML字符串：
"<Messages><Message><ID>1</ID><Title>今天心情不错！</Title></Message><Message><ID>2</ID><Title>明天又要上班了！</Title></Message></Messages>"
webservice.htc文件下载
====================================================================================
Top.aspx页面：
<HTML>
<HEAD>
  <title>WebForm1</title>
  <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
  <meta name="CODE_LANGUAGE" Content="C#">
  <meta name="vs_defaultClientScript" content="JavaScript">
  <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
  <script language="javascript" src="Message.js" type="text/javascript"></script>
<script language="javascript">

function SentOnlineMsg()
{
var accepterID = document.getElementById('drpUserId').options[document.getElementById('drpUserId').selectedIndex].value;
//alert(accepterID);

//发送在线消息
service.useService("../GetMess_WebService/GetMess.asmx?wsdl","GetMess");
service.GetMess.callService(callback,"SentOnlineMsg",accepterID);
setTimeout("SentOnlineMsg()",30000);
//alert("定时");
}

}

function LoadMenu()
{
//alert("Start");
//启动在线消息发送
SentOnlineMsg();
}
</script>

</HEAD>
<body onload="LoadMenu()">
  <form id="Form1" method="post" runat="server">

   <DIV id="service" style="BEHAVIOR: url(webservice.htc)"></div>

   <FONT face="宋体">用户切换</FONT>
    <asp:DropDownList id="drpUserId" runat="server"></asp:DropDownList>
  </form>
  </DIV>
</body>
</HTML>

===================================================================================

Message.js:

/*
消息弹出窗方法

参数说明：
width   窗口宽度
height  窗口高度
title   窗口标题
contentArray 消息内容数组
linkArray  链接地址
outTime  延时关闭时间（单位：豪秒）

调用的例子：
popMessage(214,140,'消息提醒',contentArray,linkArray,10000)

var oPopup = window.createPopup();
var popTop=0;
var mytime;
var closeTime;
var flag=0;
function innerHTML(width,height,title,contentArray,linkArray)
{

var TempArray = "";
var i=0;
var number=0;
var zindex=9999;
var html="";
var width2=width-6;
var height2=height-24;
var PopupWinId="PopupWin";
var PopupWinHeaderId="PopupWin_Header";
var PopupWinTitleId="PopupWin_Title";
var PopupWinContentId="PopupWin_Content";
var PopupWinMessageId="PopupWin_Message";
html=html+"<div id=\"service\" style=\"behavior:url(webservice.htc)\"></div>";
html=html+"<div id=\""+PopupWinId+"\" style=\"background:#E0E9F8; border-right:1px solid #455690; border-bottom:1px solid #455690;border-left:1px solid #B9C9EF; border-top:1px solid #B9C9EF; position:absolute; z-index:"+zindex+"; "+width+"px; height:"+height+"px; left:0px; right:0px;\" onselectstart=\"return false;\" >\r\n"+
    "<div id=\""+PopupWinHeaderId+"\" style=\"cursor:default;position:absolute; left:2px; "+width2+"px; top:2px;height:14px;filter:progid:DXImageTransform.Microsoft.Gradient(GradientType=0,StartColorStr='#FFE0E9F8', EndColorStr='#FFFFFFFF');font:12px arial,sans-serif; color:#1F336B; text-decoration:none;\">\r\n"+
     "<span id=\""+PopupWinTitleId+"\">"+title+"</span>\r\n"+
     "<span style=\"position:absolute; right:0px; top:0px; cursor:pointer; color:#728EB8; font:bold 12px arial,sans-serif;position:absolute;\" onclick=\"parent.ClosePopupWin()\" onmousedown=\"event.cancelBubble=true;\" onmouseover=\"style.color='#455690';\" onmouseout=\"style.color='#728EB8';\">X</span>\r\n"+
    "</div>\r\n"+
    "<div id=\""+PopupWinContentId+"\" onmousedown=\"event.cancelBubble=true;\" style=\"border-left:1px solid #728EB8; border-top:1px solid #728EB8;border-bottom:1px solid #B9C9EF; border-right:1px solid #B9C9EF;background:#E0E9F8;padding:5px;pacing=4px; overflow:hidden; text-align:left; filter:progid:DXImageTransform.Microsoft.Gradient(GradientType=0,StartColorStr='#FFE0E9F8', EndColorStr='#FFFFFFFF');position:absolute;OVERFLOW: auto; left:2px; "+width2+"px; top:20px; height:"+height2+"px;\">\r\n";
for(i=0;i<contentArray.length;i++)
{
  var tbName = contentArray[i].split("|");
  number=number+1;
  html=html+"<span style=\"cursor:hand; font:12px arial,sans-serif; color:#1F336B; text-decoration:none;\" id=\""+PopupWinMessageId+"\" onclick=\"parent.OpenWin('"+linkArray[i]+"','"+i+"')\">"+number+"."+tbName[0]+"</span><br>";

}
html=html+"</div>\r\n";
html=html+"</div>\r\n";
oPopup.document.body.innerHTML =html;
}

function popMessage(width,height,title,contentArray,linkArray,timeOut)
{
flag=0;
innerHTML(width,height,title,contentArray,linkArray);
popupWin(width,height);
window.setTimeout("CloseWin("+width+","+height+")",timeOut);
}

function ClosePopupWin()
{
oPopup.show(0,0,0,0);
flag=1;
popTop=0;
window.clearInterval(mytime);
window.clearInterval(closeTime);
}

function popupWin(width,height)
{

if( popTop<=height)
{
  oPopup.show(screen.width-width,screen.height-popTop, width, popTop);
}

else if(popTop<=height+30)
{
  oPopup.show(screen.width-width,screen.height-popTop, width, height);
}
else
{
  oPopup.show(screen.width-width,screen.height-height-30, width, height);
}
popTop=popTop+0.8;
mytime=setTimeout("popupWin("+width+","+height+");",5);
}

/*

html=html+"<style type=\"text/css\"> "+
html=html+" ";
html=html+"</style> "+

*/

//html="<LINK href=\"../css/nandasoft.css\" type=\"text/css\" rel=\"stylesheet\">";

function OpenWin(strUrl,winName)
{
var intHeight = 380;
var intWidth = 600;
var mytop=(screen.height- intHeight)/2;
var myleft=(screen.width- intWidth)/2;
var strType='resizable=no,scrollbars=no,width=' + intWidth + ',height=' + intHeight + ',left=' + myleft + ',top=' + mytop;
var win=window.open(strUrl,winName,strType);
win.focus();
}