JSFiddle - React, Tailwind, and code Playground
HTML
<form action="" method="post" name="form" id="form">
<input type="text" placeholder="Your email*" name="email" id="email">
<input type="text" placeholder="Your name*" autocomplete=off name="name" id="user_name">
<button type="submit" id="signup" value="Sign me up!">Sign Up</button>
</form>
JavaScript
if ($.trim($("#email, #user_name").val()) === "") {
$('#form').submit(function(e) {
e.preventDefault();
alert('you did not fill out one of the fields');
})
}