- From: Al Gilman <asgilman@access.digex.net>
- Date: Thu, 29 Oct 1998 21:44:38 -0500 (EST)
- To: w3c-wai-gl@w3.org
In today's GL telecon, I suggested that we should offer the creators of dynamic web pages the following idea: "take action at the right place." That is not self-explanatory, but it is perhaps explained by the "virtual ISMAP" script example discussed in the UA post copied below. Unfortunately this guideline idea depends on the idea that user agents will expose scripts by something on the order of a context menu. And we have not got consensus for that in the UA group or acceptance by the browser community. But for alternative access to script functionality, it makes sense to take a little care over what object the script is associated with. Quoting from URL: http://lists.w3.org/Archives/Public/w3c-wai-ua/1998OctDec/0009.html ISMAP-class problem with script From: Al Gilman <asgilman@access.digex.net> Message-Id: <199810031940.PAA24381@access2.digex.net> To: w3c-wai-ua@w3.org Date: Sat, 3 Oct 1998 15:40:42 -0400 (EDT) Subject: ISMAP-class problem with script Chuck described a problem event-handling script for us in the User Agent telecon a week or so ago. As I understood the scenario, it is "the same class of object as the deprecated server-side sensitive image map." I want to build on this analogy in our WAI-PF dialog with the DOM group about accessibility requirements. But I owe the example to Chuck and that meeting, so I am writing it down here first. There is a table. in the table cells there are images. There is no on-mouse-down event handler bound to any of the images, but there is one on the table. The script which handles on-mouse-down for the table, however, inspects the current mouse location to decide what to do. To perfect the ISMAP analogy, let us just say that it compares the mouse position with a disjoint set of rectangles falling entirely within the table and each one completely enclosing one image. This is a control morphology identical to a sensitive map. Now, we have established accessibility standards that say a sensitive map should be done on the user side because then the user agent can give the user verbal information about the available control actions and their prospective outcomes. In a sense, the DOM question is "Is the DOM a frame of reference where we can recognize that this is the same thing as the server-side image map pathology?" Jon has done a good job in his note about "DHTML Issues" that this is the basic usability/accessibility problem: how can the user have adequate visibility over the potential consequences of actions so that the UI merits being rated as "exhibiting predictable response?" To the user, the on-mouse-down handler is a method associated with an object, the table. I suspect that DOM 1 only covers the information associated with the table that the HTML tells us, not the behavior of its methods that the script tells us. When and how to get the model to cover and discipline what actually bites the user is one of the things that WAI-PF and the DOM WG need to discuss. Al
Received on Thursday, 29 October 1998 21:44:40 UTC