function GetXmlHttpObject(handler)
{ 
    var objXmlHttp=null
    if (navigator.userAgent.indexOf("Opera")>=0)
    {
        alert("This example doesnt work in Opera");
        return; 
    }
    if (navigator.userAgent.indexOf("MSIE")>=0)
    { 
        var strName="Msxml2.XMLHTTP";
        if (navigator.appVersion.indexOf("MSIE 5.5")>=0)
        {
	        strName="Microsoft.XMLHTTP";
        } 
        try
        { 
	        objXmlHttp=new ActiveXObject(strName);
	        objXmlHttp.onreadystatechange=handler;
	        return objXmlHttp;
        } 
        catch(e)
        { 
	        alert("Error. Scripting for ActiveX might be disabled"); 
	        return;
        } 
    } 
    if (navigator.userAgent.indexOf("Mozilla")>=0)
    {
        objXmlHttp=new XMLHttpRequest();
        objXmlHttp.onload=handler;
        objXmlHttp.onerror=handler; 
        return objXmlHttp;
    }
}