HTML Java Form input field Restrict to only allow international uk numbers e.g 447655123456-CodePudding

Im trying to find an example that would force a user to have to input 447 as the first four characters and then the remaining 9 have to be only numbers.

so if someone wanting to type 07655 123456 it would not allow. so unless you first character is a second 4 third 4 fourth 7 then the remaining is 9 numbers.

I can guess this can be done with a prefix and a restriction to numbers for the remaining 9 but from a user and ease of use they dont get it and want to type it all.

Any Advise please just a simple html form with a input field.

CodePudding user response：

HTML5 has new input type as tel which you can straight away use within input. Here, as you are not looking for any brackets () or - between digits so below is what I am suggesting as a validation. If you don't enter correct number, validation message appears on your screen.

<!DOCTYPE html>
<html>
<head>

<form>
  <label for="choose">Enter your phone number</label>
  <input type='tel' pattern='[\ ]447\d{9}' title='Required Phone Number (Format:  447999999999)'/>
  <button>Submit</button>
</form>
</html>