The following is the link for Date Validation i.e. Entered date is valid r not.
http://www.expertsrt.com/scripts/Rod/validate_date.php
function validateDate(fld) {
var RegExPattern = /^(?=\d)(?:(?:(?:(?:(?:0?[13578]|1[02])(\/|-|\.)31)\1|(?:(?:0?[1,3-9]|1[0-2])(\/|-|\.)(?:29|30)\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})|(?:0?2(\/|-|\.)29\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))|(?:(?:0?[1-9])|(?:1[0-2]))(\/|-|\.)(?:0?[1-9]|1\d|2[0-8])\4(?:(?:1[6-9]|[2-9]\d)?\d{2}))($|\ (?=\d)))?(((0?[1-9]|1[012])(:[0-5]\d){0,2}(\ [AP]M))|([01]\d|2[0-3])(:[0-5]\d){1,2})?$/;
var errorMessage = 'Please enter valid date as month, day, and four digit year.\nYou may use a slash, hyphen or period to separate the values.\nThe date must be a real date. 2-30-2000 would not be accepted.\nFormay mm/dd/yyyy.';
if ((fld.value.match(RegExPattern)) && (fld.value!='')) {
alert('Date is OK');
} else {
alert(errorMessage);
fld.focus();
}
}