JavaScript Prevent typing letters on input not working on mobile.

[Roy Harper]

I recently noticed that my website input validation of prevention of letter typing is not working on mobile. I can freely type anything on the input. While on desktop, it works just fine. What should I do?

function validateNumber(event) {
  var key = event ? event.keyCode : event.which;
  if (event.keyCode === 8 || event.keyCode === 46) {
    return true;
  } else if (key < 48 || key > 57) {
    return false;
  } else {
    return true;
  }
}

 

[OldMan]

keyCodes are probably different. Look them up for each op system