var Dom = {
	add_querystring_parameter : function(url, param, value) {
		// check if there is a ? in the url already
		var idx = url.indexOf('?');
		if (idx >= 0) {
			// check if there is something after the ?
			if (url.length+1 > idx)
				return url + '&' + param + '=' + value;
			else
				return url + param + '=' + value;
		} else
			return url + '?' + param + '=' + value;
	}
}