Pcwalton's response is good. I'll add that I think your confused about what I am saying. In the JavaScript world, the single page app is really just a pure cli

Pcwalton's response is good. I'll add that I think your confused about what I am saying. In the JavaScript world, the single page app is really just a pure client side app, no different than an app dedicated to Windows like Word. The difference is that it targets web standards for building applications, in a sense the browser is the operating system and application development environment that the OS used to provide. The key is that it's a standard, and should work the same across platforms. The fact that it's on the web is just a delivery platform for the software. Webassembly will bring the performance of these browser based applications to be on par with any native application. It's the write once run everywhere development that we've all wanted since the promise that Java made. I do think that there is a benefit to this model over Java, which is that it's more flexible than Java was in allowing for design choice, and many more languages (in large part thanks to the LLVM).