function QueryString(qs) {	// optionally pass a query string to parse
	this.params = new Object();

	if (qs == null)
		qs = location.search.substring(1, location.search.length);

	if (qs.length == 0) return;

	qs = qs.replace(/\+/g, ' ');

	// parse out name/value pairs separated via &
	var args = qs.split('&');

	// split out each name=value pair
	for (var i = 0; i < args.length; i++) {
		var value;
		var pair = args[i].split('=')
		var name = unescape(pair[0])

		if (pair.length == 2)
			value = unescape(pair[1])
		else
			value = name

		this.params[name] = value
	}

	this.get = function(key) {
		if (this.params[key] == undefined) {
			return null;
		}

		return this.params[key];
	};
}