Synthetic submit event should probably trigger form submission

[upsuper]

It seems to me that currently dispatching a synthetic submit event to a form doesn't trigger submission of the form per spec, and dispatching submit event itself is a step in the form submit algorithm.

Gecko did submit when a synthetic submit event is dispatched to the form. When we tried to fix this difference in Gecko bug 1535988, we hit a compat issue that YUI 2 bases its behavior on browser detection. The condition is like

if ((UA.ie || UA.webkit) && bSubmitForm) {
  oForm.submit();
}

This basically means any browser which intends to conform to the spec but not pretends themselves as either IE or WebKit would hit this problem.

I suggest that we make synthetic submit event trigger form submission (when the event is not defaultPrevented), and block double submission of the same form (so that the extra submit() call wouldn't affect WebKit-based browsers).

What do you think?

[annevk]

It seems rather risky to make a decision like that based on this one data point. There might be other cases where it would hurt to do this, no?

Also, this would mean adding another special case to https://dom.spec.whatwg.org/#concept-event-dispatch.

[annevk]

#3599 is somewhat related.

[domenic]

Another option is to extend the spec's Gecko compatibility mode.

[rniwa]

This seems like a pretty risky change to make based on one version of YUI as @annevk says. Maybe Gecko can add a site specific quirk for this versions of YUI? Or do you have other examples of websites that rely on this behavior?

[upsuper]

How can you add site specific quirk for such a widely used library?

[rniwa]

How can you add site specific quirk for such a widely used library?

By "site specific quirk", I don't mean to base quirk based on an URL but rather the pattern of usage that indicates that particular version of YUI. For example, WebKit used to have a quirk which got enabled based on file name from which CSS selector came from, etc... to detect some versions of media wiki for which a quirk was needed.