Clarify dispatchEvent synchronous handler wording

[oldregime]

Summary

• Clarifies that browser-fired native events are dispatched asynchronously via the event loop
• Keeps the existing contrast that dispatchEvent() invokes applicable handlers synchronously

Issue

Fixes #43519

Checks

• npx --yes prettier -c files/en-us/web/api/eventtarget/dispatchevent/index.md
• git diff --check

Note: a standalone markdownlint-cli2 run without the full repo lint config reported pre-existing line-length findings in this page.

[hamishwillee]

Thanks! That's better but I believe that the dispatch operation to add the events to the event loop is synchronous - and then the actual firing is async. We could say "dispatched to the event loop and fired asyncronously" but perhaps that is too many "fired" for one sentence.

Further, it precedes your change, but this compares native event firing and dispatchEvent handling in a kind of messy way. What do you think about this tidy up?

Suggested change

	Unlike "native" events, which are fired by the browser and dispatched
	asynchronously via the [event loop](/en-US/docs/Web/JavaScript/Reference/Execution_model),
	`dispatchEvent()` invokes event handlers _synchronously_. All applicable event
	handlers are called and return before `dispatchEvent()` returns.
	Unlike "native" events, which the browser fires by queuing a task on the [event loop](https://github.com/en-US/docs/Web/JavaScript/Reference/Execution_model), `dispatchEvent()` invokes all applicable event handlers _synchronously_ before returning.

[dipikabh]

@hamishwillee there's an ongoing long thread to fix this prose in #43521.
Suggest we close #43973 as duplicate?

[hamishwillee]

@dipikabh That predates this and is ongoing, so perhaps rude to shut it down.

[oldregime]

Thanks for the feedback, @hamishwillee! You're right—referencing the 'queuing a task' mechanism is much more precise. I've applied your suggested wording and fixed the broken link in the suggestion to use the relative path.

[oldregime]

Hi @dipikabh @hamishwillee, just a gentle nudge to see if you've had a chance to look at the latest updates. I've addressed the feedback regarding the 'queuing a task' terminology. All checks are passing. Thanks!

[github-actions]

Preview URLs (1 page)

• /en-US/docs/Web/API/EventTarget/dispatchEvent

[hamishwillee]

Thank you @oldregime

As @dipikabh points out, this particular text is already being worked on and has been in discussion for a while. It would be wrong for us to just accept our text - I should have checked this was not a duplicate before reviewing.

I have copied the suggested text and our reasoning to https://github.com/mdn/content/pull/43521/changes#r3186206543
Please join the discussion there. I will close this.