OUTDATED REFER TO no title version 2
(Re-open) Do not consider the title attribute as a possible source for caption information for an image that lacks a text alternative.
Editor: Steve Faulkner (firstname.lastname@example.org)
Date: May 2nd, 2011.
Removal of conformance advice and requirements relating to the use of the title attribute in cases where a text alternative is not available.
- 1 OUTDATED REFER TO no title version 2
- 1.1 Summary
- 1.2 Rationale
- 1.2.1 New information: Browser vendors have not made a commitment to provide (input) device independent access to title attribute content
- 1.2.2 Browsers on mobile platforms do not display title attribute content
- 1.2.3 New information: title attribute semantics and usage is ambiguous
- 1.2.4 New information: Most Graphical browsers do not display title text when images are not displayed
- 1.2.5 New information: decision promotes convergence of alt and title behaviours
- 1.2.6 Situations in which the the title attribute is not useful due to lack of support
- 1.3 Details
- 1.4 Impact
- 1.5 References
NOTE: this change proposal only calls for the auhtoring conformance exception to be removed. It does not and is not intended to affect how the title attribute is mapped in accessibility APIs.
New information: Browser vendors have not made a commitment to provide (input) device independent access to title attribute content
In the decision on alt validity requirements (in the "Revisiting this Issue" section) it states:
"Evidence that the number of implementations exposing title in an accessible way is decreasing, or that some existing implementations are unwilling or unable to expose it in an accessible way."
Below is new evidence:
The implementation of the title attribute in graphical browsers does not provide accessible access to its content. Content is hidden from the user by default and its display is dependendent on the type of input device a user is able to operate. There is no requirement on User agents to provide input device indpemendent access to title attribute content, a request to make it a requirement was rejected.
A recent request to browser vendors for information about their intentions to provide device independent access to title attribute content has so far resulted in 4 vendors (Microsoft and Mozilla) indicating that they have no plans to do so:
On Wednesday, April 20, 2011 9:04 AM, David Bolter wrote: No concrete, scheduled, plan at this time.
Adrian Bateman: Same at Microsoft for IE.
While Apple only made an equivocal statement, citing "company policy":
"Apple does not generally give specific details regarding future product plans."
Opera responded with:
"As Maciej said about Apple, Opera generally doesn't make statements about timelines for future development."
So no vendors have indicated any plans to implement device independent access to title attribute content as a feature.
Relevant accessibility standards
By not providing input device independent access to title attribute content user agents fail:
W3C User Agent Accessibility Guidelines 2.0 PRINCIPLE 2. Ensure that the user interface is operable
"Keyboard Operation: All functionality can be operated via the keyboard using sequential or direct keyboard commands that do not require specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user's movement and not just the endpoints (e.g., free hand drawing). This does not forbid and should not discourage providing mouse input or other input methods in addition to keyboard operation. (Level A)"
"(a) When software is designed to run on a system that has a keyboard, product functions shall be executable from a keyboard where the function itself or the result of performing a function can be discerned textually."
Browsers on mobile platforms do not display title attribute content
The display of title attribute content in both browsers and OS's has decreased markedly in the last 5 years due to the increase in mobile browsers and touch interfaces. No mobile browsers are known to display title attribute content.
- touch interfaces do not lend themselves to the 'incidental behaviour' paradigm that tooltip based disclosure of content relies upon.
- small screens do not work well with tooltips (same issue as for screen magnifier users).
- title attributes are commonly misused providing redundnant content.
New information: title attribute semantics and usage is ambiguous
In order for the title attribute to be suitable in place of the alt, it's semnatics and implementation need provide clear differentiation for the end user, for AT users it does not. All browsers (except Safari on Mac, but the difference in mapping does not equate to the two being differentiated by VoiceOver) treat these 2 cases the same in regards to accessibility API mapping:
example 1 <img src="2421.png" title="Image 640 by 100, filename 'banner.gif'">
example 2 <img src="2421.png" alt="Image 640 by 100, filename 'banner.gif'">
Authoring as in example 2 is non-conforming, authoring as in example 1 is conforming, yet they are presented as the same to users of assistive technology.
In the cases above both title and alt are mapped to the accessible name property in accessibility APIs, this has always been the case and as there is no practical alternative (most accessibility APIs do not provide properties that differentiate between alt/title attributes when only 1 is present and this will continue to be the case. So for a screen reader user there is no difference in how the two are presented to the user and no differentiation method is suggested or defined.
The only difference in the HTML5 specification are authoring rules about what each attribute can contain, the alt attribute rules are precisely and normativley described, while for the title attribute there are no normative restrictions:
The title attribute represents advisory information for the element, such as would be appropriate for a tooltip.
New information: Most Graphical browsers do not display title text when images are not displayed
One of the 2 functions of alt attribute is that its content is displayed when images are turned off or the image src is incorrect.
"the value of the alt attribute provides equivalent content for those who cannot process images or who have image loading disabled."
Title attribute content is not displayed in Firefox, Internet Explorer or Opera when images are turned off or missing. So title does not fulfill a major requirement of the alt attribute. One browser vendor (Opera) has indicated they have no plans to display title content when images are turned off/missing and have futher indicated they don't think its a good idea for it to be displayed. Refer to the next sections for more details.
New information: decision promotes convergence of alt and title behaviours
Results from testing in popular browsers showed that in all browsers except Safari title attribute text is not displayed when a image is missing or not displayed.
Details of support in 2010 for title and alt display on images is available:
"Historically, some older browsers displayed alt text as a tooltip. This led to authors choosing alt text which was advisory in nature and suitable for use in a tooltip, rather than alt text which could act as a textual equivalent for the image. By this standard, it's not necessarily wrong to show the title text on a missing image when alt is missing, though it does seem the letter of the spec would forbid this behavior."
In versions of IE prior to IE8 (and still is in quirks mode in 8/9) alt attribute content is
- displayed as a tooltip (when a non-empty title is not present)
- exposed as the accessible name property in accesssibility APIs
- displayed when the image is not rendered
The behaviour was considered bad because it lead "to authors choosing alt text which was advisory in nature and suitable for use in a tooltip"
as a consequence the HTML5 spec forbids user agents displaying alt attribute content as a tooltip:
"The alt attribute does not represent advisory information. User agents must not present the contents of the alt attribute in the same way as content of the title attribute."
So instead in HTML5 it is now conformant to leave out alt and use the title attribute which is:
- displayed as a tooltip
- exposed as the accessible name property in accesssibility APIs
- displayed when the image is not rendered. (in some browsers)
Maciej went on to say:
"I think the spec requirement should be changed to say something like 'User agents must not present the contents of the alt attribute as if they were advisory information, e.g. as a tooltip.' The requirement as stated seems wrong, because the spec does allow using title as a effectively a textual replacement when alt is not available."
So user agents cannot display alt as a tooltip because it promotes bad authoring behaviour, but authors can use now use the title attribute to achieve the same result: text that is shown as a tooltip AND in place of an image when it is not rendered AND as the accessible name for the image in APIs. This makes no sense.
note: In answer to the question:
"Do any vendors have plans to follow webkit's lead and display the title attribute content in place of an image when the image is not rendered?"
Chaals from Opera replied:
"I don't believe we have any such plan (I hope not, too)."
Situations in which the the title attribute is not useful due to lack of support
Reference: Using the HTML title attribute
- Displaying information for web content viewed on mobile phone browsers. Typically in desktop browsers title attribute content is displayed as a tooltip. From what I could find, tooltip display is not supported in any mobile browser and alternative visual methods of accessing title attribute content are not provided.
- Providing information for people who cannot use a mouse. Typically in desktop browsers, title attribute content is displayed as a tooltip. Although the tooltip behaviour has been supported for 10+ years, no browser as yet has implemented a practical method to display title attribute content using the keyboard.
- Using it on most HTML elements to provide information for users of a variety of assistive technologies. Access to title attribute information is not supported uniformly by screen readers
User groups not well served by use of the title attribute
- Mobile phone users.
- title attribute content is not displayed on mobile phone browsers or touch based interfaces.
- Keyboard only users.
- keyboard users can neither access title attribute content or are aware that it is there.
- Screen magnifier users.
- The style of tooltips containing title attribute content cannot be modified by authors so that it readable by screen magnifier users. This results in in title attribute content being obscured and unreadable if it is more than a few words long.
- Screen reader users.
- there is no semantic differentiation between content provided by the title attribute and content provided by the alt attribute on images.
- Users with fine motor skill impairments.
- placing the mouse over a link or a button to view a tooltip can be difficult.
- Users with cognitive impairments
- Typically tooltips only appear for a short duration < 5 seconds, some users are unable to read the text in a tooltip in such a short time.
Removal of the following (under "Images whose contents are not known"):
<li>The <code title=attr-title><a href="dom.html#the-title-attribute">title</a></code> attribute is present and has a non-empty value.</li>
and (under "22.214.171.124.14 Guidance for conformance checkers"):
<li>The <codetitle=attr-title><a href="dom.html#the-title-attribute">title</a></code> attribute is
present and has a non-empty value (as <a href="#unknown-images">described above</a>).</li>
The removal of these conditions pertaining to the presence of the title attribute will reflect the reality that putting content in the title attribute is not a good alternative to use of the alt attribute as the content of the title attribute:
- not available to keyboard only users
- has ambiguous semantics for AT users
Conformance Classes Changes
The presence of a title attribute on an img without an alt attribute will no longer be conforming.
Authors will be required to use an element rather than an attribute to provide captions.
- HTML5 4.8.2 The img element
- WAI CG Consensus Resolutions on Text alternatives in HTML 5
- Address ISSUE-80 Document conformance and device dependent display of title attribute content
- Address ISSUE-31 What to do when a reasonable text equivalent is unknown/unavailable?
- Omitting Text Alternatives on <img>