Summary:
The <do> tag provides a general mechanism for the user to act upon the current card. The representation of the <do> tag is dependent on the device and the author must only assume that the tag is mapped to a unique user interface widget, such as a button, that the user can activate.
The <do> tag may appear at both the card and deck-level:

* Card-level: the <do> tag may appear inside a card tag and may be located anywhere in the text flow.

* Deck-level: the <do> tag may appear inside a deck template, indicating a deck-level <do> tag. A deck-level <do> tag applies to all cards in the deck, and is equivalent to having specified the do within each card. For the purposes of rendering, the browser must behave as if deck-level <do> tags are located at the end of the card's text flow.

A card-level <do> tag overrides (or "shadows") a deck-level <do> tag if they have the same name. For a single card, the active <do> tags are defined as the <do> tags specified in the card, plus any <do> tags specified in the deck's template and not overridden in the card.

Non-active <do> tags and active <do> tags with a noop task are not displayed. All active <do> tags with a task other than noop will be shown in some manner. When the user activates the <do> tag, the associated task is executed.

Attributes:

Name	Data type	Mandatory	Default	Description
xml:lang	String	X		The natural or formal language of the tag or its attributes
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
type	String			Provides a hint to the browser about the author's intended use of the tag and how the tag should be mapped to the physical user interface: 'accept' (positive acknowledgement); 'prev' (backward history navigation); 'help' (request for help); 'reset' (clearing or resetting state); 'options' (request for options or additional operations); 'delete' (delete item or choice); 'unknown' a generic do element
label	String	X		Specifies a textual string suitable for labelling the user widget. To work well on a variety of browsers, labels should be six characters or shorter in length
name	String	X	Value of type attribute	Specifies the name of the do event binding
optional	Boolean	X	false	If true, the browser may ignore this element

Nested tags:
<go> <prev> <noop> <refresh>