<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Forms</title>
  <style>
    input:valid {
      background: #EEEEFF;
    }
    input:invalid {
      background: #FFEEEE;
    }
  </style>
</head>
<body>
  <section>
    <form name="myform" method="get" action="process.php">
      <input type="email" name="myemail" required>
      <input type="submit" value="Send">
    </form>
  </section>
</body>
</html>