What's the best way to automatically insert slashes '/' in date fields

Question

I\'m trying to add functionality to input date fields so as when the users enters in digits, slashes \"/\" get automatically added.

So suppose I have the following

Answer 1

Handles backspace, delete, paste, long press.

let $jqDate = $('.date-slashes');

$jqDate.bind('keyup', function(ev) {
  if (ev.which !== 8) {
    let input = $jqDate.val();
    let out = input.replace(/\D/g, '');
    let len = out.length;

    if (len > 1 && len < 4) {
      out = out.substring(0, 2) + '/' + out.substring(2, 3);
    } else if (len >= 4) {
      out = out.substring(0, 2) + '/' + out.substring(2, 4) + '/' + out.substring(4, len);
      out = out.substring(0, 10)
    }
    $jqDate.val(out)
  }
});