Pages on the world wide web may broadly be grouped into three intended uses. These are:
Additionally, the information presented on web pages may be accessed differently depending on whether the content is already known (or suspected), or whether a user is exploring the content of the page without any preconceived notion as to probable content. These two types of use may be described alternatively as “browsing” and “searching” the content of a page. The three types of application may all be browsed or searched, depending on the prior knowledge and needs of the user.
The navigation techniques that are used for these types of pages are somewhat different, and a user agent should provide the tools to navigate each type of page to users with disabilities.
When a user enters a page for the first time, and has no definite goal in mind, s/he should be provided with the ability to explore a web page displayed in a browser.
#16: Sequentially navigate to
only link elements (Open)
Historically, gateway pages
consist of collections of hyperlinks.
These pages may be formatted as lists or tables of links, or may be
formatted to look like content pages by embedding links within pages of text. In other cases, the links are embedded in a
graphic in the form of an image map.
However, in most cases, most of the information content of a site is
actually on the linked pages. Since the
functionality of the page is provided through the links, and the other elements
on the page are intended to provide context or aesthetic appeal, the user
should be able to directly access the functionality of the page, bypassing
other elements.
In order to discover the links on
such a page, the user agent should provide a facility to move the focus of the
user agent from link to link in the logical order of the page via a device
independent action. Because third party
assistive technology typically is capable of generating character codes, some
character level command should be provided to enact this method of navigation
in addition to direct selection via a pointing device.
#3: Should user agents be able
recognize markup for navigation bars
As the web evolves, pages are including navigation bars as alternatives to lists of text links. Navigation bars appear as collections of buttons or text which provide links to other pages, and may have added behaviors such as changing size or color when the mouse pointer hovers over them. The document markup for such navigation bars may be substantially different from that of traditional links, but in order to provide equivalent functionality for users with disabilities, navigation bars should be accessible both via direct selection with a pointing device and via character level commands.
When a web page is commonly used by an individual as a gateway, and the user has a significant familiarity with the content of the page, it may be more efficient to jump directly to a desired link. If the user enters a gateway page for the first time, but with a definite goal in mind, s/he may wish to quickly discover if the page contains a link to a specific destination. Finally, a user who is exploring a page may wish to distinguish between links that have been visited, and those that have not.
#21: Search for link based on
its text content (Open)
A user agent should provide the
ability to search for a web page based on the text content of the link. For example, if the user were looking for
information on Koala bears, it would be useful to be able to search for links
containing the term Koala. This will
allow the user to move directly to a link on a page, or to determine that the
page does not contain such a link.
#38: Search for a link based on
its attribute value (Open)
When a user is exploring the web,
and returns to a gateway page, s/he may wish to either return to a linked page
that had previously been visited, or to move directly to unvisited links. In either case, the user agent should be
able to search for links based on their attributes. Additionally, because the text of a link may not be identical
with the content of a link, it may be desirable to search within the text of a
URL, in addition to the content of a link.
For example, the link to http://www.biology.au/Koala.htm
might contain text like “cute, cuddly bears with vile tempers.” Searching for the text “Koala” would not
find this link. Searching within the
attribute would.
Query pages allow web sites to obtain information from users. This information might be used to place orders from an e-commerce site, to subscribe to a newsletter or magazine, or to request information from an online database. In each case, the goal is to obtain information from the user of the page. Such pages may have significant explanatory text around the data collection elements, which is helpful to the novice user, but unnecessary by the experienced user. Because a user with a disability may not be able to scroll directly to elements of interest and directly select their content with a pointing device, the user agent should provide equivalent functionality.
#22: Sequentially navigate
between forms in a document (Open)
A complex query site may have
multiple forms or equivalent embedded objects to support a range of possible
query types. A library site might have
separate forms for “Search by Author,” “Search by Title,” and “Search by
Topic.” An able-bodied user can scan a
page, and use a pointing device to select the first element of the desired
query form. Each form may be composed of many elements, and sequential
navigation of form elements on a page would be a substantial burden to a user
if this were the only way to navigate to a form that was several forms down a
page.
To provide equivalent
functionality for individuals with disabilities, a user agent should provide a
means to move through the page by form level markup. This would allow the person with a disability to jump directly to
a form, determine if the form met the desired intent, and, if not, jump
directly to the next form, without the need to move through each element of the
form.
#17: Sequentially navigate to
only form controls in a document (Open)
Once the user has located the
desired form, it is essential that s/he be able to move from form control to
form control within the form, in order to provide the functionality of the form
to the user who does not have access to a pointing device.
#24: Search for a form control
based on its attribute values (i.e. label or control type) (Open)
The user who is visiting the
on-line library, and is searching for books by a favorite author may wish to
jump directly to a form which requests information about authors. The ability to search a page by form control
attributes would provide this functionality.
#23: Search for a form control
based on text content (Open)
It is sometimes useful to search
for a form control based not on its label, but on its content. For example, some web sites evaluate data
entry at the time the data is submitted, and will not accept data that is in
the wrong format. If the user has
inadvertently made a typographical error in entering his/her address, it would
be desirable to be able to jump directly to this error to correct it. However, the form control for the address
might be labeled “Address,” “Address1,” or even “Street.” Because the labels are inconsistent, the
user may not be able to directly find the information that must be
corrected. However, since the user
knows that the item contains “Pine St.”, being able to search for form controls
based on content would allow immediate navigation to the data to be corrected,
in spite of inconsistent labeling of the control.
While many pages are used to
solicit information, or to guide users to other pages, one primary reason for browsing
the World Wide Web is to obtain information from it. A user desiring content from the web needs to be able to move
through the content of the page in blocks of content that allow access to the
information contained on the page.
Able-bodied users are able to read text on the screen, and scroll
quickly through a document, visually scanning for content of interest. In some cases, the user is actively seeking
content on a specific topic. In others,
the user is simply looking for content that will peek his/her interest, and
provide entertainment. User agents
should support both types of examination of web pages.
#20: Sequentially navigate
header elements (Open)
A well-formed document may be
structured with header elements describing a section of content, followed by
that content. The headers might form
the titles of chapters of a book, or the sections of a professional
document. One method of navigating a
long document in search of content would be to move from header to header
through the document. Since, headers
are, by their nature, hierarchical, a header navigation technique should allow
navigation by headers of different levels.
The user should be able to move from <H1> element to <H1>
element, and then move to lower level elements within a document.
#18: Sequentially navigate to
only elements with long descriptions (longdesc attribute or OBJECT content) (Open)
The user may wish to obtain
information about the embedded objects within a page, by moving from
descriptive element to descriptive element through a page. In this way, the visually impaired user, for
example, could quickly get a sense of the graphical elements on a page that are
absorbed peripherally by the sighted user.
The most important, but frequently
overlooked aspect of page browsing is navigation of the text of a web-based
document. Sighted users navigate pages
by reading them from the screen, and scrolling through the document using a
pointing device. The inability to
visually access a page, or physically access a pointing device can
substantially limit access to the content of pages by individuals with
disabilities. In order to provide
equivalent functionality, a user agent should provide the ability to shift the
point of regard through a document encompassing the content in meaningful
segments. While the page-down function
of a browser allows movement through a document in sections, the sections are
determined by the window of the browser rather than the content of the document. After shifting the view port of a browser,
the text displayed may begin in the middle of a sentence, and not be meaningful
outside of its context. To provide
equivalent access for individuals with visual deficits, the user agent should
allow changing the point of regard by paragraphs, as well as by larger block
structures.
When entering a page that has been identified as containing specific information, the user may have to do significant scrolling to find that information. It is, therefore, essential that a user agent allow the user to search for specific text within a page. The browser should provide the ability to search for the next occurrence of a segment of text without retyping the search key.
#15: Sequentially navigate
between active elements (Resolved)
Many web pages include active
elements that can provide functionality based on user actions. These include features activated by
“mouseover” and “mouseleave” events, features activated by clicking on an
object within a page, and other scripted functionality. Scripts may be attached to arbitrary
components of a page, not just to links and form controls. In order to provide equivalent access to
users with disabilities, a user agent should provide a means of locating and
activating embedded active elements.
This functionality would require moving the mouse pointer (or other
point of regard indicator) over active elements, and simulating mouse clicks in
a device independent manner.
#27: Move to the next element in
the document tree as defined by DOM (Open)
#28: Move to the child level
element of the current element in the document tree (Open)
#29: Move to the next (or
previous) sibling element in the document tree (Open)
#30: Move to the parent element
of the current element in the document tree
(Open)
One strategy for navigating a
document is to allow the user to “walk the document tree.” In this strategy, the user is able to move
from the root element of a tree throughout its structure. Such functionality requires that the user
agent provide a means of moving from any element to its first decendent, to its
prior or next sibling, and to its parent.
In a fully functional implementation, a user would be able to move from
an element to its parent, and then move directly back to the starting element,
regardless of where it falls in the sibling hierarchy.
Walking the document tree, by its nature, provides much of the functionality of navigation of a document described in earlier sections, but has the disadvantage of requiring the end user to understand the concept of the document tree, and the structure of an arbitrary document in order to predict the action of any given command.
#11: Move to the next element
with the same attributes and element type
(Open)
Examining the degrees of
functionality required for equivalent access shows that, if each of the types
of navigation were provided by separate commands, a user would have a
significant cognitive task in learning to navigate the browser. Having individual commands for navigation by
links, by link attributes, by navigation bars, by forms, by form elements, and
by headers and paragraphs would require the user to remember each type of
command to use the provided functionality.
This would significantly disadvantage users with limited cognition.
As an alternative strategy, a user
agent might be designed to allow the user to “find the next thing like this
one.” Such a browser would have to
implement a point of regard indicator that moved from block element to block element
under the control of the user. When the
user found the type of element that seemed to be significant to his or her
purposes, a command could be issued that would “find the next element like this
one. Such a command would be sensitive
to links, visited links, forms, form controls, tables, table cells, headers and
paragraphs. It would also sensitive to
attributes such as font characteristics.
In this way, even though the author of a page uses font attributes to
simulate headers, a user agent would be able to simulate moving through headers
by matching the font attributes selected.
The most significant advantage of
this strategy is that it requires minimal understanding of the document
structure and command structure by the user.
When the user finds a document section that seems to contain the type of
information of interest, a single command can move to the next similar element,
regardless of the nature of the element under consideration. A second command would find the previous
element, allowing two-way navigation throughout the document.
#26: Search for an element based
on its text content (Open)
Searching a document’s contents
should be possible by either its text content, or, given the functionality
suggested above, by the attributes of the content. When a user enters a web page that, according to their web search
utility, contains information on Koala bears, s/he may wish to locate the word
Koala on the page. Since the term may
be located many screens down a document, such search facility adds
significantly to the usability of a user agent.
Many authors use in-line markup to
indicate elements of interest. Key
words in a document may be formatted as <strong> to indicate their
importance. Key paragraphs may be
formatted in a different font, or with different indenting. These techniques
allow the visual user to quickly identify significant ideas while scanning
through a document.
To provide equivalent access to
users with visual impairments, a user agent should provide the ability to
search within a document based on the attributes of the text as well as the
content of text. A user might seek to find elements with <strong>
formatting, or elements with a specific font.