Changing colours of polygons in online study

Sorry but I can’t seem to get this to work for me, I must be doing something wrong…?
I’ve tried changing the .js in the coder and THEN syncing to Pavlovia but the incorrect, red bits from your above bit of code get uploaded (not the green bits I’ve manually changed it to).
I’ve also tried changing the .js file AFTER I’ve synced to Pavlovia (i.e., on gitlab.pavlovia.org), but then the experiment won’t run at all - it gets stuck on ‘initialising the experiment.’ Inspecting this gives me the below messages:


I’ve found a similar post on the forum (Loading module was blocked because of a disallowed MIME type) which attributes this to an incorrect output path, but mine IS set to html (like this post says it should be…?).
Any idea what I’m missing?