I reply on one bit inline, down near the "practical error" part: On Tue, Nov 15, 2011 at 12:23 PM, Joseph Scheuhammer <clown@alum.mit.edu>wrote: > All: > > This thread began as a comment by Matt King that he hasn't found a useable > ARIA combobox. The general feeling is, I think, that this is related to > the use of aria-activedescendant, and how it affects focus. > > IMHO, the current example of the autocomplete combobox suggests that there > is a subtle difference in the meaning of aria-activedescendant compared to > its original purpose. Using Larry's concept of "perceived focus", let me > try to flesh that out. > > Consider another common example where one might use aria-activedescendant: > a grid. As the user arrows around the grid, a cell is visually marked > with a focus ring to show the user which one has focus. And, the user > perceives that cell as focussed. Under the hood, however, DOM focus is on > the grid container element and remains there. The code tracks the cell > that the user has navigated to, and styles it to appear as if it has focus. > > This case is what aria-activedescendant was designed for. Instead of > using the roving tabindex technique, where DOM focus *is*moved among the > cells, DOM focus stays on a parent container, and it keeps track of the > perceived focus using aria-activedescendant. > > Compare that with the autocomplete combobox example. For me (and maybe it > is just me) perceived focus stays on the text input always. I don't > perceive focus ever moving to the list even when using up and down arrows. > The input caret is clearly blinking in that text field, and I know that if > I type any characters, they will end up there. The highlighting of list > items with up/down arrows is undoubtedly useful feedback, but I don't > perceive focus moving to the highlighted item. > > Perhaps it is a practical error to use aria-activedescendant in this case. > Since highlighting list items is extra information, perhaps it is better > handled by an aria-controls relationship. I think this might be right. Perhaps we should advocate that aria-AD not be used in these cases and in addition to your suggestion of an aria relationship perhaps a polite live region could help. D > By way of comparison, consider a tabbed pane. Here, the DOM focus and > the perceived focus remains on the tabs as the user navigates among them, > but the visible tab-panel keeps switching according to which tab has focus. > Users do not perceive the tab-panel as the focussed object (if > aria-activedescendant were used), rather, they see it as the relevant panel > associated with the tab that currently has focus (the object identified by > aria-controls). > > Is a combobox more like a tabbed pane, or more like the grid example? > >
Received on Tuesday, 15 November 2011 19:39:26 UTC