jQuery Forum

I just got bitten by an unexpected (for me at least) behaviour of the
jQuery() function:
$(), $(''), $(0), $(null) and $(undefined), all return a collection
equal to $(document).
...this causes weird things to happen when one converts a String to a
dom, when the string happens to be empty.
Somehow I expected
$('body').append( $(html) );
to be functionally equivalent to
$('body').append( html );
Is that an unreasonable expectation, and if not, is it too late to
fix?
--
Már

It seems possible to ever so slightly optimize $.className.add(),
$.className.remove(), and $.className.has() by adding an up-front
check to see if the `className` parameter is a non-falsy value (not
just `undefined`).
This would avoid triggering costly processing such as envoking $.each
loops, .splits() and functions, and even possibly document reflow
(when re-assigning unchanged values to an element).
One could also check for the existence of element.className before
attempting to remove any classNames.
It seems like a place ripe for optimization.
--
Már.

Hi.
If it hasn't been already considered (and rejected), I'd like to float
the idea of adding support for prototypal inheritance into the jQuery
core library.
Something like this...
jQuery.beget = function (proto, props) {
var F = function () {};
F.prototype = proto;
var instance = new F();
return props ? $.extend(instance, props) : instance;
};
...becomes immensely powerful - especially during plugin development
when allowing users to extend/override default options
options = $.beget($.myplugin.defaults, options || {});
...and in various other common use cases - including $.fn.data()
assignments, etc.
I for one would love to see this feature added.
--
Már

Seems like Sizzle isn't cleaning up after itself in IE.
After a few round-trips, I'm seeing a lot of this in an Element that
has it's `.innerHTML` edited and then posted to a server:
<table width="100%" cellspacing="0" done2="4" done4="4" done5="4"
done3="4" sizset="4" sizcache="4" summary="">
<tbody done2="4" done4="4" done5="4" done3="4" sizset="4"
sizcache="4">
<tr class="alt" done2="4" done4="4" done5="4" done3="4"
sizset="4" sizcache="4">
<td done2="4" done4="4" done5="4" done3="4" sizset="4"
sizcache="4">
</td>
</tr>
</tbody>
</table>
I'm also seeing tons of `jquery1234377093764="43"` attributes all
over,
even in places that I'm pretty certain I haven't bound any event-
handlers or data to (not via my code, nor via any 3rd party plugins).
I wonder if there are any plans for making Sizzle less "obtrusive" in
this regard...
(See ticket: http://dev.jquery.com/ticket/4282)
--
Már Örlygsson

I was bitten by my assumption that $.fn.not was simply an inversed
$.fn.filter() ...
...which it isn't, as it doesn't accept functions as an argument.
Is there a good reason (API-wise) for this difference?
--
Már

I just created a ticket (http://dev.jquery.com/ticket/4174) with demo/
test-cases for both versions of jQuery...
---------------------------------------
The following code produces quite different results in jQuery 1.2.6
and 1.3.1 ...
var protoElm = $('#proto b');
protoElm
.bind('click', function(e){
alert("I'm a click event!");
});
$('p')
.append( protoElm )
.prepend( protoElm );
Results in jQuery 1.2.6:
All paragraphs have a <b> element appended and prepended
Clicking all <b>s triggers an alert!
Results in jQuery 1.3.1:
The prototype <b> disappears
Not all paragraphs have a <b> element appended and prepended.
Only clicking the first <b> triggers an alert!

I just posted this ticket (with test-case) into the bug tracker:
http://dev.jquery.com/ticket/4104
For this HTML:

Select me.

This happens:
$('p:not(.test)').length == 1;
$('p:not(div.test)').length == 1;
$('p').not('p.test').length == 1;
$('p:not(p.test)').length == 0; // Fail!
--
Már Örlygsson

`$("#foo").remove()` removes all event handlers and stored data.
But, sometimes I'd like to temporarily remove an element from the DOM
for later reinjection, in which case the event and data removal
becomes a nuisance.
Is there a way to do that in jQuery - aside from writing your own
`.removeTemp()` plugin?
`$("#foo").remove(true)`
`$("#foo").remove(selector, true)`
feels like a natural way to express this.
any thoughts?
--
Már Örlygsson

I've found that in IE 6 & 7, jQuery 1.3.1 seems to return incorrect
CSS opacity values for elements that have `filter: alpha(opacity=N);`
applied in a stylesheet.
However, elements with their opacity level set with a `style=""`
attribute, return the correct number.
Additionally elements with opacity set to `0` seem to return `1` in IE
6 & 7...
Here's a test case:
http://mar.eplica.is/ie-opacity-bug-demo.html
And another test using my patched version of jQuery 1.3.1:
http://mar.eplica.is/ie-opacity-fixed.html
Direct link to the patch:
http://mar.eplica.is/ie-opacity-fix.diff
I don't know, if this bug has been fixed or rejected.
My brief search came up empty.
--
Már Örlygsson

`$('<p />').parent()` returns the <div> wrapper for the innerHTML
injection when creating the paragraph element.
This makes it impossible to distinguish between a newly created
element and an element that is intentionally wrapped in a <div>.
Smells like a bug.
Can this be fixed without breaking lots of other functionality?
possible fix would be to add something like:
while (div.lastChild) { div.removeChild(div.lastChild); }
*after* the line
elem = jQuery.makeArray( div.childNodes );
within `$.clean()`.
--
Már Örlygsson