When I first started working on the port, I didn’t know whether it would even be viable, performance-wise. I feared
that we might finish the port and find that the interface was sluggish, unresponsive, and clunky. The single-threaded
main thread to lock and block the UI, causing the dreaded “This page is unresponsive” alert in the browser.
I am happy to say that our fears were unfounded. Performance, on the desktop, seems comparable to the current
JavaSE port - and in some cases it is even better. The true test of performance, however, is on mobile devices.
On newer devices (e.g. iPhone 6, iPad Air 2) the port is quite responsive; Animations and transitions are smooth -
though not quite as smooth as in the iOS port. On the previous generation of devices (e.g. Nexus 5, Nexus 7),
I would describe the port as “usable”, but animations and transitions are a little jerky. As we move into even older
devices, the apps remain usable, but the slow responsiveness, animations, and transitions become more
So… at present, your apps should work very well in desktop browsers and quite well in new mobile devices.