[yyyk]

So toasts have a positive z-index, and the display attribute changes to none after a short while? That's awfully presentational, just as much as marquee.

Note that the github defining <toast> does not use your 'response to user behaviour' definition. It says rather: "a non modal, unobtrusive window element used to display brief, auto-expiring windows of information to a user". It could be just about any information according to this definition. That's not very semantic - all what this definition refers to is presentational.

Or if we take the other (more verbose) definition: "is a small message that shows up in a box at the bottom of the screen and disappears on its own after few seconds. It is a simple feedback about an operation in which current activity remains visible and interactive".

Yes, the latter definition uses the word "feedback" in the second sentence - but nothing there says that feedback is only in response to a user initiated operation. It could just as well have been a message about some system thingy. They key part is presentational again ("small message", "box at the bottom of the screen", "disappears after a few seconds").

[joe-collins]

Should I have prefaced my own definition with "imo"? I believe that there is a common semantic core that could be encapsulated in a new element. The closest thing to a presentational demand I would include is that they be temporary.

[yyyk]

I did not mean to be overly argumentative. I just wanted to refer to the proposal as it is. There could be a case for a somewhat different proposal like yours, say if mobile does need this and implements support. However, at the moment the proposed element is defined almost entirely by presentational demands.