Jquery if Condition that will call an Alert if string not in proper format

Question

Basically, I am trying to craft an if condition that will alert users if the do not enter their date in the proper format, i.e. the format (2011-09-20) it will alert users to this fact. Thanks in advance!

Answer 1

Just use a regular expression (and then check if it can be parsed into an actual date)

var testValue = "2011-09-91";

if(!testValue.match(/^[0-9]{4}(\-[0-9]{2}){2}$/) || isNaN(new Date(testValue)))
{
    alert("failure");
}