<optgroup>
Description
This element groups multiple options within a <select> element list together. The option groups cannot be nested within other option groups.
Example
<html>
<body>
<form>
<select name="select1">
<optgroup label="First Group">
<option>First</option>
<option>second</option>
<option>third</option>
</optgroup>
<optgroup label="Second Group">
<option>First item in second group</option>
<option>Second item in second group</option>
<option>Third item in second group</option>
</optgroup>
</select>
</form>
</body><!-- ww w .j a v a2 s. c om-->
</html>
The code above generates the following result.
