1573438 - Remove <math>'s mode attribute

Status: RESOLVED FIXED

(Core :: MathML, task)

Description

[Frédéric Wang (:fredw)]

This attribute is from MathML 1 and was probably implemented before we ever had MathML reftests. It has been deprecated from MathML 2 in favor of the display attribute (released 16 years ago) [1] and we have been sending deprecation warnings for it since Mozilla 20 (released 6 years ago) [2]. So I believe it is safe to remove it without introducing a new runtime preference.

[1] https://www.w3.org/TR/MathML2/chapter7.html#interf.toplevel
[2] Bug 553917

Comment 1

[Frédéric Wang (:fredw)]

Attachment: Bug 1573438 - Remove <math>'s mode attribute. r=emilio

Comment 2

[Frédéric Wang (:fredw)]

What's the policy here, should we wait a bit for feedback on the intent to unship thread before landing this?

Comment 3

[Emilio Cobos Álvarez (:emilio)]

It's trivial to backout, so I'd just land it and if someone raises up questions or concerns we can re-evaluate.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9ea2d91e7e91
Remove <math>'s mode attribute. r=emilio

Comment 5

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/9ea2d91e7e91

Comment 6

[Frédéric Wang (:fredw)]

Regarding the note for developers: The "mode" attribute on the <math> element can be replaced with the "display" attribute, substituing the attribute value "display" with the attribute value "block". See https://www.w3.org/TR/MathML2/chapter7.html#interf.toplevel

For backward compatibility with legacy documents, one can use the following polyfill as a Mozilla extension (for users) or as a page script (for authors): https://github.com/mathml-refresh/mathml/issues/5#issuecomment-521525157

Comment 7

[Kohei Yoshino]

Posted site compatibility note: https://www.fxsitecompat.dev/en-CA/docs/2019/mode-attribute-on-math-has-been-removed/

Comment 8

[Frédéric Wang (:fredw)]

(In reply to Kohei Yoshino [:kohei] (Bugzilla UX) (FxSiteCompat) from comment #7)

Posted site compatibility note: https://www.fxsitecompat.dev/en-CA/docs/2019/mode-attribute-on-math-has-been-removed/

Thanks! I don't think this attribute has ever been implemented in WebKit/Safari, though.

Comment 9

[Kohei Yoshino]

(In reply to Frédéric Wang (:fredw) from comment #8)

I don't think this attribute has ever been implemented in WebKit/Safari, though.

Thank you! Updated the note along with other changes in Firefox 70: https://www.fxsitecompat.dev/en-CA/docs/2019/various-legacy-mathml-features-have-been-deprecated-or-removed/

Comment 10

[Florian Scholz (Open Web Docs)]

Updated: https://wiki.developer.mozilla.org/en-US/docs/Web/MathML/Element/math#Attributes
Added to: https://wiki.developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/70#MathML
Compat data: https://github.com/mdn/browser-compat-data/pull/5047