// JScript 文件
var xmlHttp; 
var returnDom='';
function createXMLHttpRequest() { 
if (window.ActiveXObject) { 
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); 
} 
else if (window.XMLHttpRequest) { 
xmlHttp = new XMLHttpRequest(); 
} 
} 

function startRequest(url,callback) { 
createXMLHttpRequest(); 
xmlHttp.open("GET", url, true); 
xmlHttp.onreadystatechange = function handleStateChange() { 
if(xmlHttp.readyState == 4) { 
if(xmlHttp.status == 200) { 
returnDom=xmlHttp.responseText; 
if(typeof(callback)=='function')
{
callback();
}
} 
} 
}  
xmlHttp.send(null); 
}