JavaScript Date Validation

Recently while messing with dates, I noticed an odd quirk in javascript with new Date(), i.e. if someone enters an invalid date, such as 2/29/2003, javascript creates the new date as 3/1/2003.

Having a look around, I couldn't find any scripts that took advantage of this for the sake of date validation... probably someone here has done this before, but I'll post it anyway.

The idea is that if javascript creates a new Date() with a different month, then obviously the date entered is not valid. Most of the scripts I saw used some math to divide by leap year, yadda yadda yadda, but with this feature (?) of javascript, it seems unnecessary.

Right now this code only validates mm/dd/yyyy, but it should be easy to modify to support other formats:


function isDate(sDate) {
var re = /^d{1,2}/d{1,2}/d{4}$/
if (re.test(sDate)) {
var dArr = sDate.split("/");
var d = new Date(sDate);
return d.getMonth() + 1 == dArr[0] && d.getDate() == dArr[1] && d.getFullYear() == dArr[2];
}
else {
return false;
}
}


Here's a shorter version that works if you pass in the values separately:


function isDate(mm,dd,yyyy) {
var d = new Date(mm + "/" + dd + "/" + yyyy);
return d.getMonth() + 1 == mm && d.getDate() == dd && d.getFullYear() == yyyy;
}