//returns a xmlhttpobject
function getXmlHttpObject(){
    var myXmlHttp = null;
    try{
        // Firefox, Opera 8.0+, Safari
        myXmlHttp = new XMLHttpRequest();
    }
    catch (e){
        // Internet Explorer
        try{
            myXmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch (e){
            myXmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
    }
    return myXmlHttp;
}