Javascript code testers/benchmarks

Hi

I’ve been looking around web for some javascript code testers for quality, speed, but haven’t found much.
I’m looking for things which could test the speed of my scripts with different javascript engines, code quality testers, etc.

I have yet found only a code quality tool by Douglas Crockford, JSLint:
www.jslint.com/

If anyone knows any useful stuff then post, please.