Device Independence, Accessibility and Multimodal Interaction

An informative statement by the Device Independence Working Group in advance of WWW2005.

The World Wide Web is a global communications phenomenon that appears to have no bounds. It is for everyone, everywhere. But, as the Web Accessibility Initiative has shown, there are Web users who face many challenges to access the Web. Challenges such as impaired vision, limited motor capabilities or difficulties with perception that diminish their ability to use the Web. Similarly, as the Device Independence Working Group has shown, there are Web users who face challenges because of device or network limitations, including small screens, restricted keyboards and lower bandwidth. Meanwhile, the Multimodal Interaction Working Group has highlighted the opportunities for giving everyone an effective means to interact with Web applications through the modes of interaction best suited to each user and device (visual, aural and tactile).

At first, it may seem that the challenges being addressed by DI, WAI and MMI are separate and distinct. On closer inspection it becomes apparent that there are significant overlaps between all three. Thus the solutions identified by one group may be applicable to the others. Through dialogue and regular meetings, the three groups have acknowledged the mutual benefits of cooperation to address these challenges. In this document, DI explores some of the overlaps in an effort to foster further cooperation, not only between the three groups but also between the wider communities. (For an illustration of the overlap see the appendix.)

Side-by-side comparisons

When considering issues of device independence, it is common to use the "traditional" PC browser as a reference. Creating content that is appropriate to a device then becomes a two-part issue:

  1. How to provide content to devices that lack certain PC capabilities, for instance, a cell phone with a small display, or a traditional telephone with no display at all.
  2. How to take advantage of device capabilities that exceed those of a regular PC browser, for instance, speech recognition as an alternative to key strokes, and Braille strips for tactile output.

When considering issues of accessibility, it is common to use the "traditional" PC user as a reference. Creating content that is appropriate to an ability-challenged user then becomes a two-part issue:

  1. How to provide an effective experience to a user who can't use all of the device features, for instance, for users that have difficulties in typing or in reading the screen.
  2. How to take advantage of additional user capabilities, for instance, the ability to read Braille.

Both DI and WAI are addressing the needs of a user community that exhibits significant differences from the majority of Web users. Device diversity is increasing with the continuous introduction of new devices, while there is growing demand from society for the Web to be accessible to all; a demand that is increasingly enshrined in legislation.

New users and new diversities

The introduction of a new device can, in many cases, introduce new accessibility issues. For example, a browser-equipped automobile will permit the driver to discover and use Web-based location information, but only when stationary. For safety reasons, visual browsing is disabled when in motion, and the driver must then interact with the Web using voice synthesis and voice recognition. From the point of view of the Web, the user has become blind. All of the accessibility solutions that have been developed for blind Web users can now be considered as solutions for the "blind" Web-surfing driver.

Similarly, the constraints of mobile devices, such as limited keyboards, have encouraged the developers of mobile content to devise novel navigation solutions. As a result, it is becoming easier for mobile users to access Web content while using a mobile device in a single hand and with just two or three buttons. The expertise that makes this possible can be applied to accessibility solutions for users who have restricted input capabilities or who are limited in the amount of a Web page they can perceive at any given moment.

Addressing the issues

DI is overseeing the introduction of techniques and Recommendations to address the issues of device diversity. In doing so, the group is aware of the possibilities of using these solutions in support of accessibility requirements. With respect to recent work of DI, here is a brief summary of the potential use of some of these solutions:


The purpose of the CC/PP is to permit the conveyance of device characteristics and user preferences. This information may include details of assistive technology incorporated into the browser, and specific user requirements such as the preference for text instead of graphics. Version 1.0 of CC/PP is a published Recommendation.

Content Selection (DISelect)

The purpose of DISelect is to permit the selection of content from a set of alternates on the basis of decisions influenced by contextual information. Selection is a practical adaptation technique identified by DI as being universally accepted. DISelect provides a universal way to implement this technique. It will permit, for example, an adaptation solution to select non-visual content for a client who indicates such a preference.


Vocabulary provides the means of representing the context in which Web content is delivered. This includes descriptions of the device, the network, the user preferences, the available modalities and the content itself. Technologies such as CC/PP and DPF enable this information (and changes in state) to be represented and communicated, thus enabling better adaptation and the ability to react to changes in modality or preferences.


The ability to rearrange the order or structure of a Web page is essential to be able to adapt to diverse form factors. This requirement has been identified by DI and will be addressed by the group in conjunction with others, in particular CSS. The device is not the only factor that determines the appropriate layout. A user, such as the person described in the appendix, may benefit from a Web page being rearranged. For example, a broad two-dimensional page would be rearranged as a narrow one-dimensional format for viewing on a narrow mobile device, and this one-dimensional format is better suited to the linear reading nature of voice synthesis solutions.

Working together

The Web community (including the fixed and mobile users, those with rich browsing environments and those who must endure limitations) can be assured that DI is working closely with its colleagues in WAI and MMI. We encourage sharing of ideas, requirements and solutions. We also encourage the wider communities in all three areas to work together, either through sharing of knowledge in the respective public mailing lists, or through practical sharing of Web-related experiences in education, work or leisure.

Concluding remarks

The opportunity is to enable everyone to have effective access to Web content and applications, regardless of the device, or of any disabilities that users may have. W3C is tackling this goal from three complementary perspectives: DI is focusing on adaptability, WAI on what is needed for accessibility, and MMI on how to provide an effective interaction for whichever modes (visual, aural and tactile) best suits each user's particular needs.


An illustration of the overlap between DI and Accessibility.

Consider the following example. While reading this, try to discover which group is involved (DI or WAI):

Pat has been given the task of booking the evening entertainment: a musical event followed by a good meal. On the Web, Pat discovered several potentially good venues but found it hard to follow the details on the pages because there was too much text with insufficient navigation. The form to book the restaurant was the hardest, requiring Pat to type everything instead of selecting from options.

Which of the following is Pat?

Patrick is a radio presenter who is partially blind and has limited use of his hands. Although he uses a screen magnifier and sometimes a screen reader, he finds many Web pages difficult to follow. Web forms are his biggest problem because they require him to do a lot of typing, which is understandably difficult.

Patricia is a marketing manager who is always on the road. Her constant companion is her cell-phone, which is equipped to access the Web. She finds that the Web pages she wants to view will not work on her device. Of those that work, there is too much text to be able to read properly, and Web forms require too much typing with the miniature keyboard.


[1] Cascading Style Sheets:

[2] Composite Capabilities/Preferences Profile (S&V):

[3] Content Selection for Device Independence:

[4] Device Independence Working Group:

[5] Dynamic Properties Framework:

[6] Multimodal Interaction Activity:

[7] Web Accessibility Initiative:

[8] W3C at WWW2005:

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