function erzXMLHttpRequestObject(){
var resObjekt=null;
try{
resObjekt=new ActiveXObject("Mircosoft.XMLHTTP");
}
catch(Error){
try{
resObjekt=new ActiveXObject("MSXML2.XMLHTTP");
}
catch(Error){
try{
resObjekt=new XMLHttpRequest();
}
catch(Error){
alert("Ajax nicht möglich!");
}
}
}
return resObjekt;
}

function Querystring(qs) { // optionally pass a querystring to parse
        this.params = {};

        if (qs == null) qs = location.search.substring(1, location.search.length);
        if (qs.length == 0) return;
        qs = qs.replace(/\+/g, ' ');
        var args = qs.split('&'); // parse out name/value pairs separated via &
        for (var i = 0; i < args.length; i++) {
                var pair = args[i].split('=');
                var name = decodeURIComponent(pair[0]);

                var value = (pair.length==2)
                        ? decodeURIComponent(pair[1])
                        : name;

                this.params[name] = value;
        }
}

Querystring.prototype.get = function(key, default_) {
        var value = this.params[key];
        return (value != null) ? value : default_;
}

Querystring.prototype.contains = function(key) {
        var value = this.params[key];
        return (value != null);
}