/* Client-side access to querystring name=value pairs
	Version 1.3
	28 May 2008

	License (Simplified BSD):
	http://adamv.com/dev/javascript/qslicense.txt
*/
function Querystring(qs) { // optionally pass a querystring to parse
	this.params = {};

	var query_string = window.location.search;

	if (qs == null) qs = query_string.substring(1, query_string.length);
	if (qs.length == 0) return;

// 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 &

// split out each name=value pair
	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.set = function(key, val) {
	if (val == '') {
		if (key in this.params) {
			// Remove val from parameters list
			delete this.params[key];
		}
	} else {
		// Update val
		this.params[key] = val;
	}
}

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

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