<!DOCTYPE html>
<html lang="en-US">
<body>
<select>
<optgroup label="Asian Countries">
<option>India</option>
<option>China</option>
<option>Japan</option>
</optgroup>
<optgroup label="European Countries">
<option>Germany</option>
<option>Italy</option>
<option>France</option>
</optgroup>
</select>
</body>
</html>