More precise inputmode-keyword-decimal definition (minus, dot, comma)

[HolgerJeromin]

https://html.spec.whatwg.org/multipage/interaction.html#attr-inputmode-keyword-decimal

decimal: The user agent should display a virtual keyboard capable of fractional numeric input. Numeric keys and the format separator for the locale should be shown.

Currently we have no hint for entering negative values in the spec.
Furthermore we could have a definition what is "the locale" here. For example if the input element has lang="en" the keyboard could/should show a dot instead of a comma on German phones.

Current observation in the wild:
Android keyboard shows minus, dot and comma.
iOS keyboard has no minus and dot/comma depending on the user agent locale.

[HolgerJeromin]

Is this something for web-platform-tests/interop#9 ?

[annevk]

The current text is somewhat ambiguous. I agree that ideally it's based on the language of the element, but the current text reads more like it's about the language that the end user uses. I believe that's not consistent with what we do elsewhere so I'd consider this a bug.

As such it's also not a "web compat" issue and web-platform-tests/interop#11 doesn't seem to include this feature. It's also hard to test automatically.

If I were to fix this I'd start with clarifying the specification to derive the locale from the language of the element. And then file implementation bugs.

cc @whatwg/forms @mfreed7

[HolgerJeromin]

Thanks for your answer.
Please to not forget negative numbers. That was the final point why we needed to drop the attribute in our application.