Addendum: In the description's first line, "Y.one" should be "Y.on" of course.

[code] var inp = Y.one( '#main input' );

// This will cause errors
Y.on( 'available', function () {
inp.focus();
console.log( inp + ' became available' );
}, inp );
[/code]
Yes, 'available' is expecting a selector to test -- if your reference is null it will throw an error. replace 'inp' with the selector string and it should work.

[code]
// This doesn't result in any action:
/*
Y.on( 'load', function () {
inp.focus();
console.log( inp + ' loaded' );
}, inp );
*/

[/code]

The input field doesn't have a load event.

Ah, I hadn't realized 'available' requires a selector! Now that I look at the example, it isn't very clear! I think this deserves some notice as it differs from other events.

Secondly, wouldn't it be better to have Y.on throw an Exception (or return null) if the wrong parameter type is used for 'available'?

My issue is solved anyway, thanks for the quick feedback!

Adam, would it be possible to make Y.on( 'available' ) accept Y.Node instances as well as selectors?

I often have problems with IE(7) if I try to do something to nodes immediately after I've append()ed them to the DOM (e.g. simulate( 'focus') or apply an Anim()ation). Providing a selector pretty much requires an id (other ways of ensuring a particular unique element is selected are difficult, especially when you're creating DOM nodes dynamically), but I usually don't set one because it's not needed.

What I'm proposing is that Y.on( 'available' ) accepts a Y.Node. To implement, maybe it could then just use the nodes _yuid property to build a selector by itself?

Alternatively, is there some other way of delaying code until they're ready in IE (and other "slow" browsers)?
[code]
var inp = Y.Node.create( '<input type="text" name="foo">' );
Y.one( '#form' ).append( inp );
Y.on( 'available', function () { inp.simulate('focus'); }, inp ); // doesn't work in IE
[/code]

Why are you using the available event at all? That element should already be available, so that line should just be:
inp.simulate('focus');

Consider [url=http://www.jayvee.nl/yuitest/available.html]this example[/]
[code]
var inp = Y.Node.create( '<input name="test" type="text">' );
Y.one( '#main' ).append( inp );

Y.on( 'available', function () { // not required in FF
inp.focus();
}, '#main input' );
[/code]
If I append an input and try to get it to focus, this works fine in FireFox, but IE(7/8) won't do it. The weird thing is that in this test, trying to focus() doesn't work reliably at all, even if I add the Y.on( 'available' ) callback! I've also tried inp.simulate( 'focus' ) but get the same result.

I've got something very similar (but more complex) in a page and it works. Could it be that because this page is so small IE gets into timing issues?

I'll update the docs to be more explicit about 'available' and 'contentready' needing selectors.

For support with your use case, please ask in the forums (http://yuilibrary.com/forum) or in the #yui irc channel on irc.freenode.org.