<!DOCTYPE html>
<html lang="en-US">
<body>
<form action="/login.php" method="get">
<fieldset name="mylogin">
Email: <input type="email">
<br><br>
Password: <input type="password">
</fieldset>
<br>
<button type="button" onclick="form.mylogin.style.backgroundColor='#ffe6e6'">Red Background</button>
<button type="button" onclick="form.mylogin.style.backgroundColor='#f2e6ff'">Violet Background</button>
<button type="button" onclick="form.mylogin.style.backgroundColor='#ffffff'">No Background</button>
</form>
</body>
</html>