1848196 - Tabbing with the keyboard to focus into <embed>s does not work

Status: VERIFIED FIXED

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[Thomas Wisniewski [:twisniewski][PTO until the 26th]]

Attachment: testcase-sub.html

This is possible on Chromium and WebKit 176 (as of https://bugs.webkit.org/show_bug.cgi?id=259420 landing).

I'll attach WebKit's test-case, which makes the problem obvious when testing manually by tabbing multiple times to see if the embed's inputs get focus.

Comment 1

[Thomas Wisniewski [:twisniewski][PTO until the 26th]]

Attachment: testcase.html

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

In HTMLEmbedElement::IsHTMLFocusable(), the default tab index is set to -1 because HTMLEmbedElement does not override TabIndexDefault() different from HTMLObjectElement.

Comment 3

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Hmm... <embed>.tabIndex should -1 by default different from <object>...
https://wpt.fyi/results/html/interaction/focus/sequential-focus-navigation-and-the-tabindex-attribute/tabindex-getter.html?label=master&label=experimental&aligned&q=%2Fhtml%2Finteraction%2Ffocus%2Fsequential-focus-navigation-and-the-tabindex-attribute%2Ftabindex-getter.html

Comment 4

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Attachment: Bug 1848196 - Make the default tab index of `<embed>` which loaded a document to `0` r=NeilDeakin!,#dom-core

Like <object>, <embed> can load another document. However,
HTMLEmbedElement does not override Element::TabIndexDefault() and that
causes HTMLEmbedElement::IsHTMLFocusable() set the tab index to -1 so
it's skipped during the tab navigation.

Comment 5

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Okay, making <embed>.tabIndex return 0 only after loading a subdocument works.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1bbf9fc4d2dc
Make the default tab index of `<embed>` which loaded a document to `0` r=NeilDeakin,dom-core,farre

Comment 7

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/1bbf9fc4d2dc

Comment 8

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Reproducible on a 2023-08-10 Nightly build on Windows 10.
Verified as fixed on Firefox 118.0b3(20230831180026) and Nightly 119.0a1(20230831214652) on Windows 10, macOS 12, Ubuntu 22.