Yes, I was advocating simplicity of markup and simplicity of code.
Speed on a page like this is sort of meaningless. (8ms or 38ms - neither of
which is slower than an eye blink)
Even so, I would say 5 ID calls might be slower than 1 class call calling 5
objects. Its certainly uglier in the code.
My philosophy is "Try and make your html as simple and semantic as
possible. The next developer will thank you."
Glen
On 9/6/07, Michael Geary <[EMAIL PROTECTED]> wrote:
>
>
> > From: ldexterldesign
> >
> > regarding your second point about using classes instead of
> > IDs in my XHTML, i agree, but i am under the impression that
> > warranting the use of classes on elements should only occur
> > if you plan to re-use the object, otherwise ID it - i stand
> > by this ethos, but i'm not as adept with JQ as you right now,
> > so things may change. i am aware of ID overuse though and try
> > to use as few as possible. is there some sort of speed issue
> > with how JQ handles IDs as opposed to classes then?
>
> Not at all, in fact just the opposite: In typical documents, $('#myid')
> can be *much* faster than $('.myclass').
>
> I think Glen was advocating the flexibility of classes, such as the way
> they allow you to select multiple elements in a convenient
> way and call a jQuery method on all of them simultaneously. Selecting by
> class can also help you write more reusable code.
>
> But if you know you're dealing with a single element, by all means use an
> ID for speed.
>
> One interesting code design point related to this: How do you access the
> underlying DOM element(s) for a jQuery object? Normally,
> you use .each() and a callback function. But when you use an ID selector,
> it's perfectly reasonable to use [0].
>
> For example, this code *must* use .each() - or an equivalent for loop -
> because it has no way of knowing how many elements match the
> selector:
>
> function test( selector ) {
> $(selector).each( function() {
> // do something with each DOM element
> });
> }
>
> Similarly, a more hard-coded version must also use .each(), because there
> may be more than one element matching '.myclass:
>
> $('.myclass').each( function() {
> // do something with each DOM element
> });
>
> But if I saw this code, a mental alarm would go off (what if there is more
> than one match?):
>
> $('.myclass')[0].someDomMethod();
>
> However, this code is perfectly reasonable (unless you need to handle the
> case where the #myid element does not exist on the page):
>
> $('#myid')[0].someDomMethod();
>
> -Mike
>
>
