JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" />

CSS

.error {
    border: 1px solid red;
}

JavaScript

function filterNonDigits(evt)
{
  var event = evt || window.event;
  var val = event.target.value;
  var filtered = val.replace(/[^0-9]/g, '');
    
    if(filtered !== val) {
      event.target.value = filtered;
      event.target.className += " error";
    }
}

$('input').keyup(filterNonDigits);