I am using jQuery 1.7.1 and I'm trying to find out why the following code takes 4600 MS, if I change the :eq(0) to :first it is the same result.

$(tr:eq(0) td); // x10000 takes 4600ms

$(tr).eq(0).find(td); // x10000 takes 470ms

The second codes is almost 10 times as fast! And it's only written differently.

Also if I use a selector like, just selecting an ID or looking within a node:

someparent.find(#test) // x10000 takes 500ms

$(#test) // x10000 takes 100ms

$(div#test) // x10000 takes 470ms

I would say, if I pass an div#test would be faster than #test but it is 5 times slower. Why?

I have done all runs a couple of times and it is real slow if I do the same thing different.

Why is using the selector slower then using functions?