[jQuery] Re: What is the more correct/efficient selector?

[DBJDBJ]

          $("select").change(function() {
               alert( $(this).val() );
                });

Is not so good for a few reasons:

1: it forces jQuery to select all the select's on the page, and then
"somehow" to get to the one where event "onchange" was fired from.
2: it uses the slowest form of dom selection , namely by tag name
...
etc

Please get into the  habit of *always* using the 'context' argument.
when initally calling $().
And have dom node as a context argument. (
http://brandonaaron.net/blog/2009/06/24/understanding-the-context-in-jquery
)
Which in turn is forcing you to use (a lot ) more 'containers' in
order to balance the dom tree in your pages.

So, imagine there is a form on your page which contains one or more
select's:

          $("#mySelect25", $("myForm")[0] ).change(function() {
               alert( $(this).val() );
                });

Would be the preffered way ...  Or just a 'container' div that
contains our select :

          $("#mySelect25", $("myDIV")[0] ).change(function() {
               alert( $(this).val() );
                });

In real life situations you might have (for example a toolbar with
buttons etc inside it. So:

$tbar = $("myToolbarDiv", document.body ) ;

$tbar.find("button:first").click ( function () {} ) ;
$tbar.find("button:last").click(function () { } ) ;
$tbar.find("#mySelect25").change(function() {
               alert( $(this).val() );
  });

Your (real) pages will inevitably grow and the usage of context and
container elements and id's in selectors will speed up things
noticeably.

PS: find() is actually the fastest way to select, it is a straight
Sizzle call. But it needs a container *arround* what are we looking
for: $("#container").find("whatever is inside")

--DBJ