Workable like this
If you need to add a library, (and therefore use the src = … functionnality), you have to add that library directly inside your index.html page (inside the theme folder)
Did you try to refresh the page while having your developer console open in Chrome (can be opened using F12). This will probably give some more details about the error.
the console log do not indicate any errors besides the “deprecated” entries:
Best use mx.addOnload() to execute your script, after the client has finished loading. You can find some more information about it here: https://apidocs.rnd.mendix.com/9/client/mx.html
Regarding mx.addOnload() can you please refer to a how-to as I’m pretty new to Mendix.
Nevertheless I must admit, that this is not a simple solution.