dialog vs. alertdialog

[benbeaudry]

What's the actual difference between a dialog and a alertdialog?

An alertdialog is a subclass of dialog and should be modal, just like a dialog. Both roles expect the focus to be within the dialog. The only apparent difference is that an alertdialog should convey a message to alert the user. In practice, though, I think screen readers will just read out the content of dialogs even though there is no alert.

Can someone give me specific use cases for each?

[aleventhal]

Agree. It seems like any possible difference will be really minor.

I see this difference:

• An alertdialog fires an alert event, so that the screen reader should read the entire thing.
• A dialog does not, and the screen reader should read up to the first focus (hopefully all ATs do this).
  (In both cases, if aria-describedby/aria-description is set on them, then that should be read instead.)

If there are no other practical differences for the user, then perhaps we should deprecate alert dialog.

[scottaohara]

another potential difference would be a role=dialog should be considered aria-modal=false by default, where as an alertdialog could be aria-modal=true by default.

#1210

[aleventhal]

Weird, but ok. I would have thought the opposite maybe? :)

[scottaohara]

@aleventhal maybe something else for us to talk out then. I'm curious as to why you'd think the opposite.

[JAWS-test]

I guess the main difference is the behavior when the browser window doesn't have the focus.

• When a dialog is opened, something just happens on the browser window in the background and this is not noticeable with AT.
• if an alertdialog is opened, then an alert-message is sent, which makes the operating system output this message from the AT, even if the browser window is invisible in the background.

[aleventhal]

@JAWS-test thanks, that's interesting.
@scottaohara we should test this to verify it is correct.