Opera is working on a new Javascript engine named Carakan (pronounced Tsharakan) for their browser.
Google launched their Chrome web browser with a super fast V8 Javascript Engine.
Mozilla is working on TraceMonkey for the Firefox web browser.
Apple has their SquirrelFish engine which is used in Safari.
Now, Opera has announced that they are working on a new generation Javascript engine named Carakan.
Source: http://my.opera.com/core/blog/2009/02/04/carakan