Tryit Editor v1.8

Source Code:

<!DOCTYPE html>
<html>
<body>

<form action="demo_form.asp" method="get">
<fieldset name="personalia">
  Name: <input type="text" name="username"><br>
  Email: <input type="text" name="usermail"><br>
</fieldset>
<button type="button" onclick="form.personalia.style.backgroundColor='yellow'">Change background color of fieldset</button>
<input type="submit">
</form>

<p><b>Note:</b> The &lt;fieldset&gt; name attribute is not supported in IE.</p>

</body>
</html>

Result:

W3Schools.com - Try it yourself

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