// JavaScript Document
function isDate(dateStr) {
	var datePat = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)(\d{4})$/; 
	var matchArray = dateStr.match(datePat); 
	if (matchArray == null) { 
		alert("Please enter date as either mm/dd/yyyy or mm-dd-yyyy."); 
		return false; 
	} 
	month = matchArray[1]; 
	day = matchArray[3]; 
	year = matchArray[5]; 
	if (month < 1 || month > 12) { 
		alert("Month must be between 1 and 12."); 
		return false; 
	} 
	if (day < 1 || day > 31) { 
		alert("Day must be between 1 and 31."); 
		return false; 
	} 
	if ((month==4 || month==6 || month==9 || month==11) && day==31) { 
		alert("Month "+month+" doesn't have 31 days!") 
		return false; 
	} 
	if (month == 2) { 
		var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)); 
		if (day > 29 || (day==29 && !isleap)) { 
			alert("February " + year + " doesn't have " + day + " days!"); 
			return false; 
		} 
	} 
	return true; 
}