Use IA2 math attribute instead of ISimpleDOM when possible - #20049
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RyanMcCleary
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ISimpleDOM when possible
RyanMcCleary
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ISimpleDOM when possiblemath attribute instead of ISimpleDOM when possible
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Pull request overview
Improves MathML retrieval for Chromium-based browsers by preferring the IA2 math attribute (to avoid reliance on ISimpleDOM registration), with a changelog entry documenting improved reliability.
Changes:
- Prefer IA2
mathattribute inMath._get_mathMland strip embedded HTML comments before returning MathML. - Fall back to existing ISimpleDOM-based retrieval when the IA2
mathattribute is unavailable. - Add a user-facing changelog note about improved MathML reading reliability in Chromium.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
source/NVDAObjects/IAccessible/ia2Web.py |
Adds IA2 math attribute path for MathML retrieval (with comment stripping) ahead of ISimpleDOM fallback. |
user_docs/en/changes.md |
Documents improved MathML reading reliability in Chromium after NVDA start/restart. |
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
seanbudd
approved these changes
May 4, 2026
Co-authored-by: Sean Budd <seanbudd123@gmail.com>
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Link to issue number:
This serves as a fix for the math reading bug in #19813, but doesn't entirely close that issue since the underlying issue with ISimpleDOM is still present.
Summary of the issue:
NVDA can fail to read MathML in Chromium if the page was already open before NVDA starts or restarts. This seems to be due to ISimpleDOM not being registered.
Description of user facing changes:
Math is more reliably read in Chromium, even when a page is already opened before NVDA starts or restarts.
Description of developer facing changes:
The method
Math._get_mathMlnow checks the IA2mathattribute before falling back to ISimpleDOM.Description of development approach:
Update
Math._get_mathMlto use the IA2 math attribute when available, strip embedded HTML comments, and return the result wrapped in<math>. If the IA2mathattribute is not available, fall back to the existing ISimpleDOM behavior.A quick note about the embedded HTML comments: I only realized stripping of HTML comments was necessary after testing an initial implementation. It seems like Chromium inserts HTML comments into the IA2
mathattribute, which was causing parse errors in MathCAT.Testing strategy:
Known issues with pull request:
None.
Code Review Checklist: