JavaScript performance in Windows 10 is set to get even faster, following Microsoft's decision to support Mozilla's asm.js optimisations in the next version of its Chakra JavaScript engine set to appear in Windows 10. While challenging to write by hand, asm.js is leveraged principally by transpiling C/C++ code to run on the Web platform, utilizing technologies such as WebGL and Web Audio. Microsoft believes that asm.js is a step towards enabling near-native performance for the Web platform.

Asm.js as a technology offers a boost to JavaScript execution speed. In addition, asm.js is a pure subset of JavaScript and guarantees interoperability across platforms and browsers. This means that engines that support asm.js light up the new features, while engines that don’t will simply run with degraded performance.

With the addition of IE, support for asm.js will eventually appear across all three major browsers used today -- Firefox, Chrome, and IE.