//Extender Library
	//Date Obj
		// clone the current date object and return a different object with identical value
		Date.prototype.clone = function () {
		  return new Date(this.getTime());
		}
		// return the last day of this month
		Date.prototype.lastDay = function () {
		  var tempDate = this.clone();
		  tempDate.setMonth(tempDate.getMonth()+1);
		  tempDate.setDate(0);
		  return tempDate.getDate();
		}