Jquery element+class selector performance

Question

I was hoping $(\'#childDiv2 .txtClass\') or $(\'#childDiv2 input.txtClass\') perform better when selecting

Answer 1

Looks like it also depends on the density of the elements with the class among the elements of the type.

I ran the tests with Google Chrome Version 30.0.1599.69 using JQuery 1.10.1. Feel free to try it on another browser and/or using another JQuery version.

I tried to run the following tests:

1. Sparse (10% of the div's have the class) link to the test on jsbin

2. Dense (90% of the div's have the class) link to the test on jsbin

Looks like in the Dense case div.class wins, but in the Sparse case .class wins.