JSFiddle - React, Tailwind, and code Playground

HTML

<form id="contactform" action="success.php" method="post">
  <input type="text" id="name" placeholder="name" autofocus >
  <input type="text" placeholder="email" >
  <textarea placeholder="message" ></textarea>
  <input type="submit">
  </input>
</form>

CSS

.error{
    border: 1px solid red;
}

JavaScript

$(function () {
    $("#contactform").submit(function () {
        $(":input").not("[type=submit]").removeClass('error').each(function () {
            if ($.trim($(this).val()).length == 0) $(this).addClass('error');

        });
        if ($('.error',this).length) {
            return false;
        }
    });
});