function GetXmlHttpObject(handler)
{ 
    var objXmlHttp = null;
    
    if (!window.XMLHttpRequest)
    {
        // Microsoft
        objXmlHttp = GetMSXmlHttp();
        if (objXmlHttp != null)
        {
            objXmlHttp.onreadystatechange = handler;
        }
    } 
    else
    {
        // Mozilla | Netscape | Safari
        objXmlHttp = new XMLHttpRequest();
        if (objXmlHttp != null)
        {
            objXmlHttp.onreadystatechange = handler;
        }
    } 
    return objXmlHttp; 
} 

function GetMSXmlHttp()
{
    var xmlHttp = null;
    var clsids = ["Msxml2.XMLHTTP.6.0","Msxml2.XMLHTTP.5.0",
                 "Msxml2.XMLHTTP.4.0","Msxml2.XMLHTTP.3.0", 
                 "Msxml2.XMLHTTP.2.6","Microsoft.XMLHTTP.1.0", 
                 "Microsoft.XMLHTTP.1","Microsoft.XMLHTTP"];
    for(var i=0; i<clsids.length && xmlHttp == null; i++) {
        xmlHttp = CreateXmlHttp(clsids[i]);
    }
    return xmlHttp;
}

function CreateXmlHttp(clsid) {
    var xmlHttp = null;
    try {
        xmlHttp = new ActiveXObject(clsid);
        lastclsid = clsid;
        return xmlHttp;
    }
    catch(e) {}
}

function SendXmlHttpRequest(xmlhttp, url) { 
    xmlhttp.open('GET', url, true); 
    xmlhttp.send(null);
}