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

Also, if you need nested selectors, it's faster to use $().find().find()

http://jsperf.com/selector-test-id-id-id-id-class/2

$('#Mytbl .MyClass')
$('#Mytbl').find('.MyClass')

The latter is about 65% faster.