- From: Charles McCathieNevile <charles@w3.org>
- Date: Tue, 23 Feb 1999 20:00:45 -0500 (EST)
- To: WAI UA group <w3c-wai-ua@w3.org>
On Tue, 23 Feb 1999, Charles McCathieNevile wrote: I have interspersed my comments between (often lengthy) chunks of the document (look for CMN:). Where I don't see any problems, I have left out the relevant excerpt (look for SNIP) 6.1 Provide information about the document view Users that are viewing documents through linear channels of perception like speech (since speech is temporal in nature) and tactile displays (current tactile technology is limited in the amount of information that can be displayed) have difficultly maintaining a sense of their relative position in a document. The meaning of "relative position" depends on the situation. It may mean the distance from the beginning of the document to the point of regard (how much of the document has been read), it may mean the cell currently being examined in a table, or the position of the current document in a set of documents. For people with visual impairments, it is important that the point of regard remain as stable as possible. For instance, when returning to a document previously viewed, the user's previous point of regard on the document should be restored. The user agent should not disturb the user's point of regard by shifting focus to a different frame or window when an event occurs without notifying the user of the change. Disturbing the user's point of regard may cause problems for users who have movement impairments, who are blind, who have visual impairments, who have certain types of learning disabilities, or for any user who cannot or has chosen not to view the authors representation of information. CMN: This paragraph (above) could be significantly trimmed without losing any content. SNIP 6.1.9 [Priority 2] When a document is loaded or when requested by the user, make available document summary information. CMN: This is too vague. What information is required? 6.1.11 [Priority 3] Provide the user with information about document loading status (e.g., whether loading has stalled, whether enough of the page has loaded to begin navigating, whether following a link involves a fee, etc.) CMN: This is also very vague. Perhaps this should be combined with 6.1.9, and made explicit as to what tyes of information are required. 6.2 Provide information about document structure Hierarchical navigation (through the document tree) is useful for efficiently navigating the major topics and sub-topics of a document. 6.2.1 [Priority 2] Allow the user to view a document outline constructed from its structural elements (e.g., from header and list elements). 6.2.2 [Priority 2] Allow the user to navigate the document tree. 6.2.3 [Priority 2] Allow the user to navigate sequentially among headers. 6.2.4 [Priority 2] Allow the user to navigate sequentially among block elements (e.g., paragraphs, lists and list items, etc.) 6.2.5 [Priority 2] Allow the user to search for an element in the current document based on its text content. In case of a match, the selection should be moved to the element. CMN: This section could be structured much better. The checkpoints are, so far as I can see, as follows: 1. Allow the user to navigate the document's structural tree [p2] 2. Allow the user to generate and navigate a tree based on teh semantics of a DTD [p3] Technique: For an HTML document, construct a tree where headers are considered children of preceding headers with greater priority, and block-level elements are considered children of headers. Amaya does something like this in its 'outline' view. 3. Allow the user to search for content. In case of a match, move the selection to the content [p2] 4. Allow the user to search for an element, by specifying text content or the content of descriptive attributes (eg TITLE, ALT). In case of a match, move te selection to the element [p3] 6.3 Provide information about events It is important to alert users, in an output device-independent fashion, when important events occur during a browsing session. To avoid confusion that the effects of scripts may cause, users should be notified when scripts are executed (or be able to disable scripts entirely). This is also important for security reasons; users should be able to decide whether to allow scripts to execute on their machines. 6.3.1 [Priority 1] Allow the user to navigate among elements with associated event handlers. CMN: Is this relevant to UAs which do not handle the events? I suspect not. Should it apply to navigating the children of an element which handles bubbled events? I suspect so. All Children? Harder to say. 6.3.2 [Priority 2] Alert the user when scripts or applets are executed. 6.3.3 [Priority 3] Provide information about document changes resulting from the execution of a script. CMN: I suggest that 6.3.2 and 6.3.3 be rewritten as follows: 1. Provide notification of content and structure changes to the Document Object Model. [p1] 2. Provide notification of style changes to the Document Object Model. [p2] 3. Provide information about content and structure changes to the Document Object Model. [p2] 4. Provide information about style changes to the Document Object Model. [p3] Charles McCN --Charles McCathieNevile mailto:charles@w3.org phone: +1 617 258 0992 http://purl.oclc.org/net/charles W3C Web Accessibility Initiative http://www.w3.org/WAI MIT/LCS - 545 Technology sq., Cambridge MA, 02139, USA --Charles McCathieNevile mailto:charles@w3.org phone: +1 617 258 0992 http://purl.oclc.org/net/charles W3C Web Accessibility Initiative http://www.w3.org/WAI MIT/LCS - 545 Technology sq., Cambridge MA, 02139, USA
Received on Tuesday, 23 February 1999 20:00:47 UTC