Re: Measuring DOM performance

John Resig wrote:
>> Covers in what sense?  It's one thing to test insertion of a single node
>> into a parent. It's another to test insertion of a subtree.  Oh, and the
>> behavior might depend on the nodes being inserted (do they have names or
>> ids?), on the parent (is it display:none or not?  is it actually in a
>> document?) and some other things.
>>
>> That's all one single appendChild DOM API.
> 
> Covers in the sense that it uses the method for some form of testing
> (the particulars will, naturally, need to be analyzed further). It
> sounds like you're more interested in comprehensive regression tests -
> whereas Dromaeo is more optimized towards analyzing the performance of
> the most-commonly performed tasks (crossed by most DOM methods).

My main concern on the subject of "measureing DOM performance" is having 
tests that measure *only* the DOM. Many times you end up testing the 
performance of for example the layout engine as well. Any time you do 
modifications in a document that is rendered layout code has to kick in.

Sometimes the layout code ends up not doing anything (for example if you 
modify things inside a display:none node), however it can take some time 
before we realize that nothing needs to be done.

/ Jonas