- From: Charles McCathieNevile <charles@w3.org>
- Date: Sat, 31 Jul 1999 18:12:25 -0400 (EDT)
- To: Jon Gunderson <jongund@staff.uiuc.edu>
- cc: ij@w3.org, w3c-wai-ua@w3.org
It seems to me that searching is an example of a direct navigation technique. Sequential navigation can also be done only on the basis of a structure, which may (or in fact may not) be a hierarchy. On the Web, in a structured language such as HTML or XML (even in poorly-written examples of the language) navigating the structure which is defined by the formal syntax of the language is a helpful strategy. In HTML in particular, there is an alternative strategy which is useful - that of navigating certain types of elements. The two types of navigation that are outside the formal structure, but still often useful, are navigation of active elements to the exclusion of others (most browsers, including internet explorer, lynx, netscape, opera, w3 and probably others, allow this). The other is navigation by header elements. To my knowledge this is part of opera and w3. It seems we should have a requirement for search navigation, and that it should cover renderable content (which includes values of the alt and title attribute, although we may need to define that explicitly since it is only implicit in the document). We should also require some form of structure navigation. I am not sure whether we should specify more than that as requirements, although I would suggest that navigation of active elements needs to be a distinct requirement, and that navigation of header elements be a strongly recommended technique for structured navigation in HTML-reading User Agents. Charles McCN On Fri, 30 Jul 1999, Jon Gunderson wrote: Guideline 8: Provide navigation mechanisms JRG: Proposed Sub Head Text Users need to be able to navigate the web content. Speech and Braille users especially need to have advanced navigation techniques, since speech and dynamic Braille displays offer only a temporal or very limited view of the document at one time. Users need to be able navigate both active and non-active elements using strategies that support the users current familiarity of the document and the task they are trying to accomplish. The following are four basic types of navigation strategies user agents need to support: Sequential: Move sequentially between a set of element types based on the linear order of the element(s). This type of functionality is important for exploring the contents of a new document. The user knows they will view all elements that are part of the sequential navigation. Direct: Move directly between an element or a set of elements based on the element content or numerical position of the element. This type of functionality is important for faster access to web content when they know the location of the information of interest. This often happens when the user is using a frequently visited document. Searching: Search for an element based on element content or attributes. All elements or only a sub set of elements maybe part of the search. This function is important to users that are looking for particular key words or other type of web content to efficiently identify if the information is in the document and move to the element containing the information. Hierarchical: Based on the document model tree move between the logical relationships between elements. This type of navigation allows the user to efficiently move between logical units of the document. This can be very useful for strongly structured documents like books or instructional materials. Jon Gunderson, Ph.D., ATP Coordinator of Assistive Communication and Information Technology Division of Rehabilitation - Education Services University of Illinois at Urbana/Champaign 1207 S. Oak Street Champaign, IL 61820 Voice: 217-244-5870 Fax: 217-333-0248 E-mail: jongund@uiuc.edu WWW: http://www.staff.uiuc.edu/~jongund http://www.als.uiuc.edu/InfoTechAccess --Charles McCathieNevile mailto:charles@w3.org phone: +1 617 258 0992 http://www.w3.org/People/Charles W3C Web Accessibility Initiative http://www.w3.org/WAI MIT/LCS - 545 Technology sq., Cambridge MA, 02139, USA
Received on Saturday, 31 July 1999 18:12:29 UTC