1550635 - window.document.caretRangeFromPoint is not supported in Firefox

Status: ASSIGNED

(Core :: DOM: Core & HTML, defect, P3)

Description

[Karl Dubost💡 :karlcow]

The lack of window.document.caretRangeFromPoint might get us blocked from using the site https://coda.io/

Reported initially on https://webcompat.com/issues/30408

Steps to reproduce:

On https://coda.io/signin
Firefox is redirected to https://coda.io/unsupported-browser?continueTo=%2Fsignin
On this page, they are pledging they are in the process of supporting other platforms.

Impersonating Chrome UA we can avoid the redirection, and access the application. After the sign up process, the application fails because of the lack of window.document.caretRangeFromPoint

That doesn't mean that if Firefox supported it, it would solve all issues for this case, but that's a starting point it seems.

This is currently supported by Blink, WebKit, EdgeHTML
not supported by Trident and Gecko.
https://developer.mozilla.org/en-US/docs/Web/API/Document/caretRangeFromPoint

Here an example of polyfill for it
https://github.com/Abel-Jr/OurSite/blob/55c221dd8abf474a1075c5d3a817eaae97b73fce/wp-includes/js/dist/dom.js#L614-L647

Comment 1

[Mike Taylor [:miketaylr]]

We should file a bug in the compat standard for this, at least.

Comment 2

[Hsin-Yi Tsai (she/her) [:hsinyi]]

Coda now is working on Firefox (even still without the caretRangeFromPoint support) , but not on Fenix.
Hi Karl, do you think you can help us do further investigation to understand the root cause of the issue on Android/Fenix? Thank you.

Comment 3

[Karl Tomlinson (:karlt)]

Guessing Hsin-Yi may have meant other Karl.

Comment 4

[Karl Dubost💡 :karlcow]

Let's see if Adam has an opinion about Fenix and Coda.
Does the site work or is used on Google Chrome too?

Hsin-Yi, When you say this is not supported on Fenix? In which ways?

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

Clear a needinfo that is pending on an inactive user.

Inactive users most likely will not respond; if the missing information is essential and cannot be collected another way, the bug maybe should be closed as INCOMPLETE.

For more information, please visit auto_nag documentation.

Comment 6

[Thomas Wisniewski [:twisniewski]]

This would help us to pass the WPT https://wpt.fyi/results/css/css-contain/content-visibility/content-visibility-080.html, which Safari and Chrome both pass.

Comment 7

[Gregory Pappas [:gregp]]

Attachment: WIP: Bug 1550635 - Implement document.caretRangeFromPoint

Comment 8

[Olli Pettay [:smaug][[e-mail]]]

Happened to notice this bug. Are you planning to ask review for the patch?

Comment 9

[Gregory Pappas [:gregp]]

Happened to notice this bug. Are you planning to ask review for the patch?

Yes.

This would help us to pass the WPT https://wpt.fyi/results/css/css-contain/content-visibility/content-visibility-080.html, which Safari and Chrome both pass.

I investigated this test a few months ago and it still fails even with the caretRangeFromPoint implementation. My memory is a bit fuzzy but I think the problem is content-visibility: hidden nodes get returned by nsLayoutUtils::GetFramesForArea, which is strange.

Probably, a new bug needs to be filed for this test.

Comment 10

[Gregory Pappas [:gregp]]

Attachment: Bug 1550635 - Implement document.caretRangeFromPoint r?#dom-core,smaug

Comment 11

[Hsin-Yi Tsai (she/her) [:hsinyi]]

Link to jira https://mozilla-hub.atlassian.net/browse/FFXP-3167, also adding tentative scheduling info.