docs: clarify <dialog> Esc close request behavior

[ross-u]

Description

Corrects the explanation of how a modal <dialog> is dismissed when the user presses the Esc key. It clarifies the sequence of events, cancel followed by close, if not prevented, and explains that no explicit return value is provided in this case leaving dialog.returnValue as an empty string.

Motivation

I would like to help and contribute to the MDN documentation and thought to give it a shot with this small issue first. 🙂

Additional details

Related issues and pull requests

Fixes #41656

[github-actions]

Preview URLs (1 page)

• /en-US/docs/Web/HTML/Reference/Elements/dialog

[chrisdavidmills]

Hi @ross-u, and thank you for your work in fixing this issue.

I've provided a suggestion to tighten up the text a bit, however, I think there is a bigger concern here — the behavior works as described, but only in Chrome.

If you try it in Firefox and Safari, the returnValue is set to an empty string when you press Esc, only if you haven't already selected a value from the dialog dropdown or pressed the dialog "Cancel" button. If you've done one of those two things, then on subsequent presses of the "Show the dialog" button, when you press the Esc key, the returnValue remains set to the previously selected dialog value.

I don't know if this is old behavior, and Chrome's behavior has been updated to spec behavior, or something else. But it is worth investigating this and thinking about how to communicate it in the doc.