Performance of jQuery Selectors with ID

Question

I know in jQuery if we use ID to select elements,it\'s so efficient.I have a question about this selectors:

please consider this 3 selectors:

Answer 1

A direct ID selector will always be the fastest.

I've created a simple test case based on your question...

http://jsperf.com/selector-test-id-id-id-id-class

Selecting nested ID's is just wrong, because if an ID is unique (which it should be), then it doesn't matter if it's nested or not.