Intent to ship: Event-based form participation

[John Dai]

Summary: As of Firefox 71 I intend to turn Event-based form participation
on by default. It has been developed behind the dom.formdata.event.enabled
preference. It allows for introspection and manipulation of what will be
submitted with a form element through a new formdata event.

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1518442

Standard: <https://drafts.csswg.org/selectors-4/#location>
https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#the-formdataevent-interface
and https://xhr.spec.whatwg.org/#dom-formdata (see
https://github.com/whatwg/html/pull/4239 for the PR).

Platform coverage: All

Preference: dom.formdata.event.enabled

Devtools bug: N/A

Other browsers:

Blink: Fixed on the trunk (
https://bugs.chromium.org/p/chromium/issues/detail?id=825684)

WebKit: Hasn't implemented yet AFAIK (
https://bugs.webkit.org/show_bug.cgi?id=193231).

web-platform-tests: See the links in the PR referenced above.

Secure contexts: Not restricted

Is this feature enabled by default in sandboxed iframes? No.

[Daniel Veditz]

On Fri, Sep 6, 2019 at 3:07 AM John Dai <jd...@mozilla.com> wrote:

> Is this feature enabled by default in sandboxed iframes? No.
>

But it's not specifically disabled in sandboxed frames or behind a
non-default preference setting, right? If a sandboxed frame has allow-forms
then this event is available along with all the other normal form features?

-Dan Veditz

[John Dai]

On Fri, Sep 6, 2019 at 7:11 PM Daniel Veditz <dve...@mozilla.com> wrote:

> On Fri, Sep 6, 2019 at 3:07 AM John Dai <jd...@mozilla.com> wrote:
>
>> Is this feature enabled by default in sandboxed iframes? No.
>>
>
> But it's not specifically disabled in sandboxed frames or behind a
> non-default preference setting, right?
>

Right, it's nothing special done for sandboxed frames.

If a sandboxed frame has allow-forms then this event is available along
> with all the other normal form features?
>
>

Yes.

- John Dai