Developing complex kepubs

Hello everyone,

I'm writing a book with complex layout and some very simple Javascript.
My goal is to sell on Kobo store, only for the devices with pen support, so I think the format should be kepub. Is this correct?

Each time I made a modification, that works on Calibre ebook editor, I have to connect my device, copy the file, disconnect the cable, and test it (mainly to find nothing works at all and having to try a new strategy).

Development is going really slow (and I'm also stressing my device battery).

Is there a way to speed up the testing? A kind of "simulator" for the webkit renderer used by Kobo devices for kepubs?

How can I check in advance if some CSS and Javascript features are supported or not?


Thank you
Ignazio