This app was mentioned in 1 comment, with an average of 3.00 upvotes
If you really want cross-platform in one code, go for Xamarin.Forms. Near native performance on both platforms, leaving out the pitfalls of JavaScript and web-based apps in general (though bringing in new ones like dependency on a third-party framework, plus lagging behind a bit, also some performance loss of adding another layer).
But, it brings a few things in: - High level of code sharing (up to 99%) - Per-platform customization with ease - Resource sharing (localization, images, icons, etc.) - Simplified bug fixing on all three platforms (should the bug come from common code, e.g. a bad URL) - Being able to use native services as you wish, or passing control over to a native page
Given the hate against Xamarin on this sub I'm pretty sure I'll get a lot of downvotes, but I'd like to show off an app to all the haters: TV2 Live Play Store, App Store, Windows Store (low ratings are due to a technical fault on server-side during the big launch)
This app was written completely in Xamarin, partly by me.