var xmlhttp;
function getReturn(Url)  //提交为ashx页面路径, 返回页面的值
{
    Url += "&datatime="+new Date();
    try { xmlhttp=new ActiveXObject("Msxml2.XMLHTTP") } 
    catch (e) 
    {
         try {
                   xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
             }
         catch (E) 
             {
                   //alert("请安装Microsofts XML parsers")
             }
    }
        
    if ( !xmlhttp && typeof XMLHttpRequest != "undefined" ) 
	{   
		xmlhttp=new XMLHttpRequest() 
	}         
    try 
    {
        xmlhttp.open('GET',Url,false);   
        xmlhttp.setRequestHeader('Content-Type','application/x-www-form-urlencoded')
        xmlhttp.send(null);    
        
        if((xmlhttp.readyState == 4)&&(xmlhttp.status ==200)){
             return xmlhttp.responseText;
        }
        else{
           return null;
        }
    }
    catch (e) 
    {  
         //alert("你的浏览器不支持XMLHttpRequest对象, 请升级"); 
    }

    return null;
}