var explorer, netscape4, netscape6;
var theDOM, theSuffix, hiddenKeyword, dhtml;

if (document.all) {explorer = true;}
else if (document.layers) {netscape4 = true;}
else {netscape6 = true;}

if(explorer){
   theDOM = "document.all";
   theSuffix = ".style";
   hiddenKeyword = "hidden";
   dhtml = true;
}

if(netscape4){
   theDOM = "document";
   theSuffix = "";
   hiddenKeyword = "hide";
   dhtml = true;
}

if (netscape6) {
  theDOM = "document.getElementsByTagName('*')";
  theSuffix = ".style";
  hiddenKeyword = "hidden";
  dhtml = true;
}

function GetXmlHttpObject(handler) {
    var objXmlHttp=null;

    if (navigator.userAgent.indexOf("Opera")>=0) {
        alert("This doesn't 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;
    }
}