Why WebAssembly is a game changer for the web — and a source of pride for Mozilla and Firefox

https://medium.com/mozilla-tech/why-webassembly-is-a-game-changer-for-the-web-and-a-source-of-pride-for-mozilla-and-firefox-dda80e4c43cb

With today’s release of Firefox, we are the first browser to support WebAssembly. If you haven’t yet heard of WebAssembly, it’s an emerging standard inspired by our research to enable near-native performance for web applications.
This new standard will enable amazing video games and high-performance web apps for things like computer-aided design, video and image editing, and scientific visualization. 

WebAssembly runs entirely within the Web Platform. This means that developers can integrate WebAssembly libraries for CPU-intensive calculations (e.g. compression, face detection, physics) into existing web apps that use JavaScript for less intensive work.
Modern web apps are complex computer programs, with client and server code, much of it written in JavaScript. 

The idea is  to build a true virtual machine in the browser that would be capable of safely running both JavaScript and high-speed languages at near-native speeds.