The docs for HTMLMediaElement.defaultPlaybackRate state that setting the value to 0.0 will produce NOT_SUPPORTED_ERR, however, I am not able to recreate this in any browser. As an example:
Firefox
Version 91.0.2
Build ID 20210823123856
> var v = document.createElement("video");
> v.defaultPlaybackRate = 0.0;
0
Is this the correct method to produce the error above? I’m not sure what I could be missing.
Hi @greg-el and welcome to the community 
I can reproduce your result on Firefox Dev Edition 92 and Chrome 92. In my opinion your code is fine and should trigger this error. I’m not sure if it’s a documentation bug or an issue with Firefox and Chrome themselves. Maybe you could ask on the MDN Matrix chat and/or post an issue on the MDN GitHub page. The technical writers are rarely on this forum.
Have a nice day!
Michael
Thanks for opening the issue on GitHub!
The change is now live on MDN. 