- Important note: This Wiki page is edited by participants of the User Agent Accessibility Guidelines working group (UAWG). It does not necessarily represent consensus and it may have incorrect information or information that is not supported by other Working Group participants, WAI, or W3C. It may also have some very useful information.

User Agent issues effecting A11y

From WAI UA Wiki
Revision as of 19:15, 5 January 2012 by Glowney (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

In-page links broken

If you follow an in-page link (one that ends in #someinpagelink) on one of the Webkit browsers (Chrome and Safari and pre-IE8) the point of regard and viewport of the browser moves, but the keyboard focus remains with the originating anchor. The next time a user hits TAB (or whatever) to move to the next anchor, the focus moves to second anchor on the page, NOT the next anchor following the current point of regard in the current viewport.

Tooltips

Tooltips (the little popups that display the 'title' attribute of an element) are not accessible from the keyboard. That is, if you arrow over some element, such as <acronym title="situation normal all fouled up">SNAFU</acronym>, the tooltip does not popup.

Longdesc

Accesskeys

Browsers don't show that there are accesskeys in a page, nor what they are or how to activate them. Given that explanations by sit authors are often out of date with regard to browsers, and that different browsers allow different keys, this is a problem.

Opera has a relatively painless way to find out if there are accesskeys - activate the accesskey menu (shift-esc by default). The Excesskey extension for Opera shows if there are accesskeys defined by a visible notice in the browser UI, and allows the user to decide which keys should be used as accesskeys (e.g. to match her particular keyboard, or preferences).

How browsers react when an accesskey is pressed varies widely in terms of:

  • what modifier key(s) are used to trigger the accesskey
  • if multiple elements share an accesskey, which is used
  • whether the keyboard focus moves to the element
  • whether the element is scrolled into view
  • whether the element is activated

In particular, allowing the user to cycle through elements with conflicting accesskeys allows much more efficient access to them than sequential navigation through all operable elements, but it also makes it more difficult to use them in preprogrammed macros.

Browser

Modifier

Conflict

Chooses

Moves Focus

Scrolls

Activates

Windows

Alt+

Yes

Yes

Yes

Windows

Alt+

Conflict

Next

Yes

Yes

No

Firefox 3

Alt+Shift+

Yes

Yes

Yes

Firefox 3

Alt+Shift+

Conflict

FIRST

Yes

Yes

No

Firefox 8

Alt+Shift+

Yes

Yes

Yes

Firefox 8

Alt+Shift+

Conflict

Next

Yes

Yes

Yes

Chrome 16

Alt+Shift+

NO

NO

YES

Chrome 16

Alt+Shift+

Conflict

LAST

NO

NO

YES

Safari 5.1

Alt+Shift+

NO

NO

YES

Safari 5.1

Alt+Shift+

Conflict

LAST

NO

NO

YES

Opera 11.11

Shift+Esc,

Yes

Yes

Yes

Opera 11.11

Shift+Esc,

Conflict

FIRST

Yes

Yes

YES

Gnome

Ctrl+

?

?

?

?

Gnome

Ctrl+

Conflict

?

?

?

?

KDE

Alt+

?

?

?

?

KDE

Alt+

Conflict

?

?

?

?

Generated Content

In some browsers generated content doesn't work at all, and in others it is not made available to screen readers.

Opera makes this content available to screen readers @@test case.

Plugin trap

Plugins generally trap the keyboard focus, so it is now possible to use the keyboard with them. However, most plugins have no way to release the focus back to the rest of the page - once you navigate in, you're stuck within the plugin.

I *believe* IE does something useful here - if anyone knows, I'd love to find out. Yes, a user has always (IE 4+) been able to tab into a plugin navigate around and tab out the 'top' or bottom of a plugin (Quicktime, Flash, Real, etc.)

Firefox has issues with this, since version 1. It does not see objects from the keyboard. you cannot tab into them. it just skips the object.

Javascript blackhole

CSS Overflow

  • in caret browsing, user unable to enter the overflow box to scroll through content.
  • test case ??

Printing

  • UA truncate long lines (sometimes only 2 or 3 characters)

CSS DOM access ??

  • a group of <p> can be defined by CSS to function as 'grid' / 'table' how is UA to know relationships?

placeholder and other attributes need to be reported in a11y API

  • html5 (pattern, placeholder, step, etc. )

User understandable rendering of Element Names and Roles

The addition of new semantic elements and roles within HTML5 implies that the elements must be understandable by users of assistive technologies. Authors can use a variety of techniques to supply human readable labels that name the element. In cases where the UA does not identify an authored label, the UA is suggested to announce the element name. For example, the <details> element has an optional <summary> element that provides a label for the content of the detail. If the summary element is not used, the HTML5 specifications states:

The first summary element child of the element, if any, represents the summary or legend of the details. If there is no child summary element, the user agent should provide its own legend (e.g. "Details").


http://dev.w3.org/html5/spec/Overview.html#the-details-element

To support internationalization, semantic element names or roles, reported by the UA in lieu of an author specified replacement text, must be localized by the UA before passing to the Accessibility API.

UI interface Messages (such as "remember Password")

many times when completing a form that contains a password, the UA will inquire if the user wants the UA to save the password for that page (important accessibility concern for many). I have not been able to find a keyboard mechanism for accessing these items.

  • Firefox 8 - box appears near top of screen with a 'key' image. and text "remember password for "someone@somewhere.com" on somesite.com?" the is a "close X" and a pulldown (combobox) that starts with "remember password". no keyboard access, jaws cannot find it.
  • Chrome 15 - the box appears at the very top of content under the address bar. It too has a "key icon" and the text "do you want google chrome to save your password?" and 2 buttons "save password" and "not for this site"; and a 'close X". can't find a way to access the information or the buttons (not in the tab order) with the keyboard. Jaws announces "alert, do you want google chrome to save your password? save password not for this site close" but I cannot access the buttons or hear the message again.
  • IE 8 - the box appears. it is a system alert (system call), fully keyboard accessible, fully readable and navigable from the keyboard.