Carakan, intended to be world's fastest JavaScript engine, will be released in as-yet-undetermined version of the Opera browser Opera is working on a JavaScript engine, called Carakan, which is ...

The Moddable SDK provides a JavaScript engine for IoT development supporting greater than 99% compliance with the ES2017 specification, starting at less than 32KB.

This is not to say that the IE9 JavaScript engine is a slouch. Microsoft is revamping its JavaScript engine for the IE 9 release, making a number of changes that should speed performance.