Hi

Whilst I am not aware of any issues with Firefox and Lubuntu, I use Firefox on Xubuntu without any problem.

Are you using the SNAP version from GNOME software or are you installing a copy you have downloaded from Mozilla?

The copy of Firefox is the already preinstalled version that came with lubuntu. It is strange how it will run for a few minutes without a fault and then slowly start to disrupt the video and then just slow down.

Maybe not enough RAM? When I gave my Virtual Machine that runs Lubuntu 2 GB RAM instead of 1, it worked better.

I have noticed this slow down problem is not limited to Lubuntu it also occurs on other Linux variants.

The symptom in common is as follows

1) The problem only appears to occur while running Youtube videos even though having the workstation run a video by itself does not affect the system 2) All get the message something like a web page is slowing firefox and then minutes after Firefox either closes or gives a "gah" message about crashing.

I suspect Googles youtube is transmitting something Firefox is not able to interrupt correctly.

Is there a way to find what web site is slowing Firefox as shown in the yellow header message displayed by firefox?

I wonder if you fully support HTML5 players like many sites are using now days (instead of Flash Plugin) like the one used on Youtube.

See https://www.youtube.com/html5/ as all check marks should be blue. If any are red then you may not have packages like FFmpeg installed.

Even if you do have all check marks as blue, there is a possibility your system does not work with VP8/VP9 so well so this extension may help on Youtube. https://addons.mozilla.org/firefox/addon/h264ify/

Since you use Ubuntu there is the Ubuntu Restricted Extras that includes FFmpeg if you do not have such installed.

https://help.ubuntu.com/community/RestrictedFormats https://en.wikipedia.org/wiki/Ubuntu-restricted-extras

The new Firefox 64.0.2 update may help with the Youtube stuttering.

https://www.mozilla.org/firefox/64.0.2/releasenotes/

Thanks James.

I will give it a try but I am skeptical because this issue locks up lower power CPU machines.

Version 64.02 is not avaiable to Linux yet as of Jan-22-2019.

Can Firefox identify the web site that causes it to produce the message "web page is slowing firefox "

mace2 said

Version 64.02 is not avaiable to Linux yet as of Jan-22-2019.

Firefox 64.0.2 has been available from Mozilla for Windows, Mac and Linux since January 9, 2019.

www.mozilla.org/firefox/all/

Linux distro provided builds and updates of Firefox can sometimes vary in availability.

From my location in Canada, Ontario neither of my Linux distros have upgraded after specifically updating to Firefox 64.0 as of Jan-26-2019

Can Firefox identify what causes it to display "A web page is slowing down your browser. what would you like to do?"

Version 64.02 was not made available to Linux. as of Feb-2-2019 it went to version 65