JSFiddle - React, Tailwind, and code Playground
HTML
<div id="konsole"></div>
JavaScript
var validate = function(value) {
//var pattern = /^[a-z\'\.\- ]+$/i;
var pattern = new RegExp("^[_a-z0-9-\\+]+(\\.[_a-z0-9-]+)*@[a-z0-9-]+(\\.[a-z0-9]+)*(\\.[a-z]{2,})$","i");
var o = pattern.test(value);
return (o)?'T':'F';
};
$('#konsole').html(validate('qwertyuiopasdfghjklzxcvbnm@qwertyuiopasdfghjklzxcvbnm.qwertyuiopasdfghjklzxcvbnm'));