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Clarifications to definition of "active element"

From: Ian Jacobs <ij@w3.org>
Date: Thu, 25 Jan 2001 19:33:36 -0500
Message-ID: <3A70C5E0.D2B2520@w3.org>
To: w3c-wai-ua@w3.org

Based on some comments from Eric, I've attempted to clarify
the definition of active element. The key clarifications are:

  1) Content determines what is an active element.

  2) The state of the user's interaction with the document may
     limit which elements are active (examples are given).

  3) Not all user interactions involve active elements (e.g.,
     text selection and copying to the clipboard).

  4) The role of "active element" is subject to applicability.

The full definition follows.

 - Ian

An active element is a piece of content with associated
behaviors, that the user may trigger (or, "activate") either
through the user interface or through an API.

Content always determines what constitutes an active element. For
instance, the HTML 4 [HTML4] specification defines a number of
active elements: links, image maps, form controls, element
instances with a value for the "longdesc" attribute, and element
instances with scripts (event handlers) explicitly associated
with them (e.g., through the various "on" attributes). The role
of an element as an active element is subject to applicability.

The state of the user's interaction with that content may limit
which elements are active. For instance, an element may be
"deactivated" by a script as the result of the user's interaction
with the content. Or, an element may only be active during a
given time period (e.g., during part of a SMIL 1.0 [SMIL]
presentation). Or, the user may be viewing content in "read-only"
mode, which may deactivate some elements.

The user may interact with content without necessarily activating
active elements. For example, selecting an element's text and
copying it to the clipboard is clearly user interaction but does
not make that element an active element. (The element may also be
an active element, but only by virtue of how the author has
encoded it, not by virtue of the selection functionality provided
by the user agent.)

The consequence of triggering an active element depends on the
element. For instance, when a link is activated, the user agent
generally retrieves the linked Web resource. When a form control
is activated, it may change state (e.g., check boxes) or may take
user input (e.g., a text entry field). See also the definition of
event handler.

Most operating environments use the content focus to indicate
which active element will be triggered on user demand.
Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Thursday, 25 January 2001 19:33:38 UTC

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