I don't quite understand what "non-capturing" means -- I'm still
pretty green when it comes to regexps -- but the rest of this makes
sense. Clearly, a generalized regex-based solution isn't as trivial
as I made it out to be, but at least this'll work for a specific
application in a pinch.
You know, thanks to your tip, I just realized that I'm still on
Prototype 1.5.0. Thought I'd upgraded all my projects, but missed
this one. We'll see if 1.5.1 helps.
Altay
On May 28, 3:04 pm, Tom Gregory <[EMAIL PROTECTED]> wrote:
> For a specific application where you know the value of classes you
> can get away with using a regex, but because it's a fragile
> implementation, it might still be wise to avoid. (A simple == is
> better.) The reason it's fragile, is the regexp would also match the
> valid class name "myclass2". You can't just wrap the text string in
> "\b" looking for word boundaries, because '-' is valid in class
> names, but triggers a "word boundary".
>
> I typed out a handful of other possible optimizations for
> hasClassName based on my recollection of how it was implemented.
> Then I checked the source, and found these optimizations were all
> implemented sometime around the tail end of last year (the old code,
> which is what I remembered, was horribly inefficient). Make sure
> you're using a recent Prototype version. The core team put a lot of
> work into speedup of $$, et al.
>
> ... One possible speedup of the current hasClassName code (which _is_
> based on a regex), would be to make the groups non-capturing: several
> of the js references I have indicate the regex is faster that way.
> It may be worth testing.
>
> TAG
>
> On May 28, 2007, at 10:42 AM, [EMAIL PROTECTED] wrote:
>
>
>
>
>
> > Aha, if I change my custom function to use Element.hasClassName(elt,
> > 'myclass') instead of elt.className=='myclass' , then it jumps from
> > 16ms to ~250ms. This matches $$('div.blah'), which also took
> > ~250ms.
>
> > So, FWIW, if you don't need Element.hasClassName -- that is, you're
> > only dealing with a single class -- it looks like you can score an
> > order of magnitude speed improvement by using "if
> > elt.className=='myclass'" instead.
>
> > Whoa! Hold on... even elt.className.match('myclass') is way faster
> > (16ms) than hasClassName. And that takes care of the multiple-
> > classname issue, right?
>
> > Has anyone done any detailed profiling of hasClassName? Looks like
> > improvements in that might speed up IE's $$ significantly.
>
> > Altay- Hide quoted text -
>
> - Show quoted text -
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