JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="check"/>
<p id="hotm"><input type="text"/></p>

CSS

p { color:blue; margin:8px; }

JavaScript

$(function(){
    var myString = /@hotmail/ig;
    $("#check").bind('keyup checkvalue', function() {
        $('#hotm')[myString.test(this.value) ? 'show' : 'hide']();
    }).trigger('checkvalue');
});