NVDA becomes unresponsive on Firefox in some webpages

[bingen13]

Steps to reproduce:

Open https://www.xunta.gal/dog/Publicados/2019/20191127/AnuncioCA01-251119-0001_es.html with Firefox.

Actual behavior:

NVDA says loading document, and Firefox (or NVDA, not sure) stops responding to keyboard input.

Expected behavior:

Webpage loads and can be read normally.

System configuration

NVDA installed/portable/running from source:

NVDA installed.

NVDA version:

NVDA 2019.2.1.

Windows version:

Reproduced on Windows 7 and Windows 8.1.

Name and version of other software in use when reproducing the issue:

Firefox 71.0 64 bit.

Other information about your system:

Other questions

Does the issue still occur after restarting your PC?

Yes. It happens on two different computers.

Have you tried any other versions of NVDA? If so, please report their behaviors.

No.

[Brian1Gaff]

Yes I found this on a web site called milkandmore which is a home delivery site in the UK. I ended up blipping the power button and heard an nvda ding before the computer shut down. I used waterfox on the site, but then encountered a very odd effect where the displayed visible picture was not what nvda was reading. Has anyone else seen this effect in windows 7? Brian bglists@blueyonder.co.uk Sent via blueyonder. Please address personal E-mail to:- briang1@blueyonder.co.uk, putting 'Brian Gaff' in the display name field. Newsgroup monitored: alt.comp.blind-users -----

[Adriani90]

Can you reproduce this with NVDA 2019.3 Beta 1?

[davidacm]

This is a very large document. process html documents in Firefox is very slow compared with chrome. I ran some tests comparing the performance of screen readers with different tasks. NVDA is the fastest loading html documents in any browser, but in firefox this task always takes a long time for any screen reader, even NVDA.

I think that if you wait for a long time, the document will be loaded. If you try it with chrome, the process will take a few seconds.

I don't know if the performance when processing html documents in Firefox can be improved. But is Firefox fault, I think.

[bingen13]

I was holding off upgrading to 2019.3 due to some add-on incompatibility issues, but I have now reproduced it with 2019.3.1. and Firefox 73.0.1 64-bit.

[Adriani90]

Closing as duplicate of #9383.