Looks like Qt webassembly port is targeted for 5.11? That combined with Qt 5.10 webgl streaming might allow for simple browser app...

I am aware of multiple attempts to get qt running inside the browser in the past with varying sucess...but the reason I'm making this post is that I just I noticed Qt actually has an official issue to make a webassembly port with version indicated as 5.11 https://bugreports.qt.io/browse/QTBUG-63917 and they seem to be activlely commiting code to

http://code.qt.io/cgit/qt/qtbase.git/log/?h=wip/webassembly
http://code.qt.io/cgit/qt/qtdeclarative.git/log/?h=wip/webassembly

And they have a few very basic demos. Of course there is much more that will need to be done before libmscore can run in webassembly of course, but at least that is something that could be on the horizon.

I also tried out Qt 5.10's new webgl streamer abilitiy out of curiosity, whereby QtQuick applications can be rendered in the browser with WebGL (using primarily the GPU I presume) but with the actual compiled C++ stuff running in the background (either on localhost or another computer on the network) as a separate process.

I was pondering on IRC earlier today about maybe having an extremely simplified QtQuick GUI for libmscore. Just enough for basic score navigation and simple edits. That could work as a simplified mobile app, suitable for making basic scores like leadsheets while away from a computer, and even as a simplified desktop app. And then maybe if webassembly works then maybe a Chrome book could run libmscore in webassembly with a simplified QtQuick GUI frontend.