- From: Artur Ortega <Artur@ortegalink.com>
- Date: Sun, 1 Jul 2012 00:24:56 +0100
- To: public-web-notification@w3.org, w3@norbertlindenberg.com
Accessibility of Web Notifications Modern web browsers and mobile devices support built-in accessibility. Good examples are VoiceOver on iphone/ipad, AppleTV or Macs. Google's Chrome provides the ChromeVox screen reader. Screen readers make content of web browsers perceivable, understandable and operable for blind and visual users as long the content follows the W3C's Web Content Accessibility Guidelines 2.0 (WCAG 2.0). Screen readers read the web content in the programmatically defined language to make content perceivable and understandable to blind and visual impaired users . Any non-textual content has to provide a textual alternative to make the information readable and therefore perceivable for blind and visual impaired users. For making sure web content is operable for screen reader users it's important the interaction is provided in a device independent way. Web Notifications must meet the WCAG 2.0 Guidelines to grant equivalent access of these notifications to disabled users. Some of the WCAG 2.0 guidelines are overlapping with i18n because screen readers are able to read text in a huge variety of languages and local accents and can switch between these instantly depending on language definitions. If no or a wrong language is provided the content could be read in the wrong language or accent which could make the read content impossible to understand. Because the content in Web Notifications don't rely on web content (e.g. HTML), the specification has to be reviewed against WCAG 2.0 itself: "In particular, notifications as specified here only can contain text and icon content. In the future, notifications generated from web content may wish to contain web content themselves, but that is outside the scope of this document." * title: The title is textual content. For making sure the title of the Web Notification is read correctly by the screen reader it has to provide additionally the used language. Not having any meta information about the language of the "title" is conflicting with WCAG2.0 Guideline 3.1 Readable: "Make text content readable and understandable." - especially 3.1.2 Here some further explanation of the importance to provide language information for the title: http://www.w3.org/TR/UNDERSTANDING-WCAG20/meaning-other-lang-id.html Proposed fix: an title-lang element analog to title-dir. * title direction: Meta information wich is important to display and to read the title in an understandable way. * origin: Predefined meta information which will be only read programmatically and won't have an obvious impact on accessibility. * body: The body has identical requirements as thte title of a Web Notification: The body is textual content. For making sure the body of the Web Notification is read correctly by the screen reader it has to provide additionally the used language. Not having any meta information about the language for the "body" is conflicting with WCAG2.0 Guideline 3.1 Readable: "Make text content readable and understandable." - especially 3.1.2 Here some further explanation of the importance to provide language information for the body: http://www.w3.org/TR/UNDERSTANDING-WCAG20/meaning-other-lang-id.html Proposed fix: an body-lang element analog to body-dir. * body direction Identical to title direction: Meta information wich is important to display and to read the body in an understandable way. * tag: The tag member is only used for programmatically dealing with multiple instances of the messages. * icon: An icon can provide important information (importance or confidentiality of mail) which wouldn't be available for blind or visual impaired users without textual alternatives. An icon needs an ALT text and the used language of the alternate text. This means the Web Notification conflicts with Guidelines 1.1 and 3.1.2 . WCAG 2.0 Guideline 1.1 "Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language." Further information can be found at: http://www.w3.org/TR/UNDERSTANDING-WCAG20/text-equiv.html Proposed fix: an icon-alt and icon-lang element * URL Is only a programmatical way to access data of the icon and has no obvious implication on accessibility of Web Notifications. The Web Notification document mentions additionally that the notification " object offers a click event". A click event is not a device independent event. Blind screen reader users usually don't use a mouse and won't "click" any object. They probably will try to fire an event with the keyboard or with a touch event on a touch screen device. This description conflicts with WCAG 2.0 Guideline 2.1. Some further explanation can be found at http://www.w3.org/TR/UNDERSTANDING-WCAG20/keyboard-operation.html It would be additionally important to provide implementation guidelines to ensure accessibility. There are several areas not covered by this document wich would be essential for users with disabilities, e.g. WCAG2.0 Guidelines 1.2, 1.3, 1.4, 2.2, 2.3 & 2.4. Artur Ortega
Received on Sunday, 1 July 2012 20:57:18 UTC