JSFiddle - React, Tailwind, and code Playground

by sajadhaibat

HTML

<input id="firstname" placeholder="first name" onkeyup="lettersOnly(this)">

JavaScript

$(document).ready(function () {
        lettersOnly(input);
    });
function lettersOnly(input) {
    var regex = /[^a-z]/gi;
    input.value = input.value.replace(regex, "");
}