function isDate(dateStr)
{
	var datePat = /^(\d{1,2})(\/|-)(\d{1,2})(\/|-)(\d{4})$/;
	var matchArray = dateStr.match(datePat); // is the format ok?
	if (matchArray == null)
	{
		alert("Please enter date as dd/mm/yyyy");
		return false;
	}

	month = matchArray[3]; // parse date into variables
	day = matchArray[1];
	year = matchArray[5];
	if (month < 1 || month > 12)
	{ // check month range
		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)
	{ // check for february 29th
		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; // date is valid
}

function checkDOB()
{
	var sForm = document.forms['theForm'];
	var dob = sForm.elements['*dob'].value;
	if( isDate(dob))
	{ checkrequired('theForm'); }
}