JSFiddle - React, Tailwind, and code Playground

by Peter Peter

HTML

<input class="number" value="20100100">

JavaScript

$(document).ready(function(){
  $('input.number').keypress(function(event){
      // skip for arrow keys
      if(event.which >= 37 && event.which <= 40){
          event.preventDefault();
      }
      var $this = $(this);
      var num = $this.val().replace(/\./g, '');
      // the following line has been simplified. Revision history contains original.
      $this.val(num.replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1\."));
  });
});