Javascript Date Validation ( DD/MM/YYYY) & Age Checking

Question

I\'ve started to work on Javascript recently. What I am testing is checking the DoB in valid format. Next step will be checking the age.

What my HTML code includes

Answer 1

It is two problems - is the slashes the right places and is it a valid date. I would suggest you catch input changes and put the slashes in yourself. (annoying for the user)

The interesting problem is whether they put in a valid date and I would suggest exploiting how flexible js is:

function isValidDate(str) {
  var newdate = new Date();
  var yyyy = 2000 + Number(str.substr(4, 2));
  var mm = Number(str.substr(2, 2)) - 1;
  var dd = Number(str.substr(0, 2));
  newdate.setFullYear(yyyy);
  newdate.setMonth(mm);
  newdate.setDate(dd);
  return dd == newdate.getDate() && mm == newdate.getMonth() && yyyy == newdate.getFullYear();
}
console.log(isValidDate('jk'));//false
console.log(isValidDate('290215'));//false
console.log(isValidDate('290216'));//true
console.log(isValidDate('292216'));//false