Clarify detail value of synthetic click event

[masayuki-nakano]

What is the issue with the HTML Standard?

https://html.spec.whatwg.org/multipage/webappapis.html#fire-a-click-event

Firing a click event at target means firing a synthetic pointer event named click at target.

The section nor "Firing a synthetic pointer event named e" section does not define about detail. The value is "click count" if the event name is "click". Mozilla gets a interop bug report about this. When you click an HTMLLabelElement, only Firefox sets the detail of synthetic "click" event to the source event's value. However, the other browsers set it to 0. Although the value is odd because 0-times click causes the "click" event, however, according to this comment, the value is used by React to consider whether the click event is synthetic one or user initiated one. Therefore, it may make sense Mozilla to align the behavior to the others. (Note that I've not checked the other synthetic "click" events' detail value, e.g., typing Enter on <a href="..."> and <input type="submit">.)

Ideally, there should be a new attribute to indicate whether synthetic one or not. However, it's impossible to expect that all React instances will be replaced with newer version soon. Therefore, keep using the detail for this purpose must be reasonable.

Additionally, pointerId and pointerType should also be clarified too. See my comment in the bug too.

[masayuki-nakano]

And also this explanation must web developers to understand the detail value etc is copied from the original event.
https://html.spec.whatwg.org/multipage/forms.html#the-label-element:the-input-element

as if the element itself had been triggered by the user

So, this should be corrected too.

[domenic]

I think the spec is pretty clear on this already? It says to leave them at their default values, which is what other browsers are doing.

[masayuki-nakano]

@domenic Thank you for quick reply!

I think the sentence in HTMLLabelElement definition made me misled at least. And Chrome uses non-default value for pointerId. They set -1 but its default is 0.

[masayuki-nakano]

Oh, about the pointerId, it's defined by the Pointer Events. However, it's hard to realize that from the HTML spec's definition.