Summary:
The optgroup element allows the author to group related option elements into a hierarchy. The browser may use this hierarchy to facilitate layout and presentation on a wide variety of devices.

Attributes:

Name	Data type	Mandatory	Default	Description
id	String	X		A unique name for the tag within the deck
class	String	X		A name of a class of which the tag is a member
xml:lang	String	X		The natural or formal language of the tag or its attributes
title	String	X		Specifies a title for this element, which may be used in the presentation of this object.

Nested tags:
<optgroup> <option>