This is because genDataFromText is defined inline in the main page after shaderoo.js loads.
Edit: now that I think about it, just because shaderoo.js is loaded first, doesn't mean getDataFromText will by called immediately. I don't have the time to debug or even just read someone else's code right now, so I'll just leave it at that.
The second:
NotAllowedError: The play method is not allowed by the user agent or the platform in the current context, possibly because the user denied permission.
Alas Firefox is failing to tell me where exactly in the code the error is coming from.
I also see this warning:
Loading failed for the <script> with source “http://127.0.0.1:8081/socket.io/socket.io.js?_=1585039727308”.
oh, thanks for the comprising debug info...
yes, the first error might not be crucial...
i think i tracked down the reason, its due to some new code-inline-image feature i'm currently testing. some lines too long in the shader code - firefox doesn't seem to like that... i'm on it...
and the socket stuff is for remote osc-connections (you'd have to start a small server-script locally to use that - see shaderoo help-page)
its trying to communicate to an (optionally started) osc-bridge-script. (you can download this at shaderoo.org (see help section) and start it manually on your localhost to be able to communicate to an OSC-device to adjust parameters - e.g for VJ'ing)