JSFiddle - React, Tailwind, and code Playground
by ChrisStanyon
HTML
<input id="email" />
<p id="response"></p>
JavaScript
var expr = /^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/;
$("#email").keyup(function () {
var response = expr.test( $("#email").val() ) ? "Looks Good!" : "Invalid";
$('#response').html(response);
});