JSFiddle - React, Tailwind, and code Playground

by pradeep

HTML

<div class="newsletter-signup">
    <input type="text" />
</div>
<br />
<div id="valid"></div>

JavaScript

$('.newsletter-signup input').on('keyup', function(){
    var valid = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/.test(this.value) && this.value.length;
    $('#valid').html('It\'s'+ (valid?'':' not') +' valid');
});