[iLoch]

Small recommendation for folks looking to use JS for Windows development (I understand this is just a runtime, but people may be inclined to combine these two things): do not use WinJS for any reason. It's undoubtably the worst UI "framework" I've ever used. Completely inflexible (HTML and styles defined in private and inaccessible methods, swallows events, monolithic functions) and riddled with bugs and incomplete features. Really surprised it's an official Microsoft project. I don't mean to disparage the developers of it, but it's really bad. Don't use it if you value your time or peace of mind and plan on customizing it in any meaningful way.

[prplhaz4]

So, have you had a positive experience with any alternatives in the same use case?

[iLoch]

I'd recommend copying any particular CSS transitions they use, and looking at the computed properties of components in order to recreate any particular WinJS components you need. I'd also recommend you evaluate WinJS yourself and see if it fits your needs - but if you suspect you'll be doing anything more that the default then you may not have a fun time.