function Querystring(qs) {

	this.params = new Object()
	this.get=Querystring_get
		
	if (qs == null)
		qs=location.search.substring(1,location.search.length)
	
		if (qs.length == 0) return
		
		qs = qs.replace(/\+/g, ' ')
		var args = qs.split('&')
		
		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
		}
	}
	
	function Querystring_get(key, default_) {
		if (default_ == null) default_ = null;
		
		var value=this.params[key]
		if (value==null) value=default_;
		
		return value
	}