JSFiddle - React, Tailwind, and code Playground
by eleonore
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Форма</title>
</head>
<body>
<form action="">
<p>Пожалуйста,заполните обязательные поля.</p>
<p>Имя: <input name="user" required="required" /><span></span></p>
<p>Возраст: <input type="number" size="10" value="1" step="1" /><span></span></p>
<p>E-mail: <input type="email" required="required" /><span></span></p>
<p>Сайт: <input type="url" /><span></span></p>
<p><input type="submit" value="отправить"></p>
</form>
</body>
</html>
CSS
input:valid+span:after{
content:url(../../html/pic/galochka.png);
padding-left:5px;}
input:invalid+span:after{content:url(../../html/pic/chrest.png);
padding:5px;}