How to measure the perfomance of the jQuery code

Question

I know some selectors are faster than others, and of course our own methods can be faster or slower.

Is there any software/app that analyzes cpu usage or even is able to compare/benchmark among versions?

Answer 1

Heck yeah!

jsPerf — JavaScript performance playground

What is jsPerf?

jsPerf aims to provide an easy way to create and share test cases, comparing the performance of different JavaScript snippets by running benchmarks.