It's a subset of Javascript that constrains the feature-set so that optimizations can be applied. This post is announcing that Firefox nightly has added those o

It's a subset of Javascript that constrains the feature-set so that optimizations can be applied. This post is announcing that Firefox nightly has added those optimizations, so you can use the spec and get the speed bump. It's particularly good for transpiled languages, as they can easily target this subset. http://asmjs.org/faq.html http://asmjs.org/faq.html