It occured to me that I don't know how to do this from a custom button. So for example I have a simple app.js as a base file and I want to inject test pages sitting on my domain, the pages will be like custom classes that I can simply test out (as I'm having trouble rendering multiple items using tabpanel).

create a button ok
add a tap handler which will load in the file, but using the framework where would I load it into ?
I want my new custom class to fully as much as possible replace my app.js though as its getting loaded into it I suppose I need to always have it.

this is the closest thing I can think of ..!/...nel-method-add using add.

but here is a link to expanding this idea to a different subdomain