如何在jQuery中优化CLASS函数

Question

I'm profiling JavaScript using dynaTrace AJAX edition.

According to the tool's "Hot Spots", the following jQuery method is using the majority of execution time:

CLASS(*, *, undefined, *, undefined, false): false

...it has over 700 invocations on my page.

What is this call and how can I optimize it?

I'm using jQuery version 1.4.2. The performance issues are primarily in IE6 and IE7.

Answer 1

If possible, upgrade to jQuery 1.4.3 which has major improvements in this area for newer browsers...by optimize, I mean this doesn't even get called most of the time. Instead it's using the querySelectorAll() if it exists , making the entire selector process much cheaper.

Answer 2

Most likely, you should be optimizing the selectors you're passing into jQuery, not jQuery's selector engine itself. Perhaps you could identify the most common selectors you use, or find a way to identify the slowest. We may be able to help optimize those if you provide them.