Java Script Validation not working in mobile browser

Question

I am trying to make validation to accept only numbers (no letters), It works on the computer browser but stopes when using the mobile browser. Below is the code:

    $(document).ready(function () {
    const $input = document.querySelector("#phMidPane_ctl04_txtID");
    const NUMBER_ALLOWED_CHARS_REGEXP = /[0-9\/]+/;
    $input.addEventListener("keydown", event => {
      console.log(NUMBER_ALLOWED_CHARS_REGEXP.test(event.key));
      if (!NUMBER_ALLOWED_CHARS_REGEXP.test(event.key)) {
        event.preventDefault();
      }
    });
    $input.addEventListener("keypress", event => {
      // alert(2);
      if (!NUMBER_ALLOWED_CHARS_REGEXP.test(event.key)) {
        event.preventDefault();
      }
    });
  });