/* Client-side access to querystring name=value pairs
	Version 1.2.4
	30 March 2008
	Adam Vandenberg
*/
function Querystring(qs) { // optionally pass a querystring to parse
	this.params = {};
	this.get=Querystring_get;
	
	if (qs == null);
		qs=location.search.substring(1,location.search.length);

	if (qs.length == 0) 
		return;
		
    this.QueryString = qs;

// Turn <plus> back to <space>
// See: http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13.4.1
	qs = qs.replace(/\+/g, ' ');
	var args = qs.split('&'); // parse out name/value pairs separated via &
	
	this.length = args.length;
	this.exists = Querystring_exists;
	this.SetValue = Querystring_SetValue;

	this.Array = new Array();
		
// split out each name=value pair
	for (var i=0;i<args.length;i++) {
		var pair = args[i].split('=');
		var name = unescape(pair[0]);
		
		var value = (pair.length==2) ? unescape(pair[1]) : name;
		
		this.Array[i] = new Array(name, value);
		this.params[name] = value;
	}
}

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

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

function Querystring_SetValue(key, value) {
    var qs = "";
    if (this.exists(key))
    {
        // already exists - replace //
        for (var i = 0; this.length; i++) {
            qs += (qs=="") ? "?"+this.Array+"="+this.Array[i] : "&"+this.Array+"="+this.Array[i];
        }
    }
    else
    {
        qs = (this.QueryString()=="") ? "?"+key+"="+value : "&"+key+"="+value;
    }
    return qs;
}