queryselectorAll usage

I am currently upating my organisations custom JS library and one thing I am looking to introduce is querySelectorAll.

Looking at compatibility it will run in modern browser and for older browsers I wi开发者_开发知识库ll use feature detection:

if (document.querySelectorAll) {
            var nodes = context.querySelectorAll(queryValue);
} else {
    var nodes = context.getElementsByTagName(queryValue);
}

Are there any considerations that I should be aware of when using this method or is it good for production?

All opinions valued

Main difference between the two is that:

getElementsByTagName

...will return a "live list", and

querySelectorAll

...will not.

Since this seems to be only for selection by tag, I'd probably ditch the qsa, so you can have the live list if needed. I've got a feeling that qsa may be slower in some browsers as well, but haven't tested it.

EDIT:

This test shows a big performance difference between the two in Chrome 13.