I ran into this same problem today and wrote up this quick plugin that accepts a boolean or function:

$.fn.extend({

showIf: function(fn)

{

var result;

switch (typeof fn) {

case 'function':

result = fn.call(this);

break;

default:

result = fn;

}

if (result) {

$(this.show());

} else {

$(this.hide());

}

return $(this);

}

});

Usage example:

// Show all LI's based on value of condition

var condition = true;

$('ul.tabs li').showIf(condition);

// Show all LI's that contain exactly 3 anchors

$('ul.tabs li').showIf(function()

{

    return ($(this).find('a').length == 3);

});

I hope this helps :)

-Hector

On Tue, Nov 18, 2008 at 11:13 PM, Dylan Verheul <dylan.verheul@...> wrote:

On Tue, Nov 18, 2008 at 19:58, Karl Swedberg <karl@...> wrote:
> On Nov 18, 2008, at 9:02 AM, Dylan Verheul wrote:

> Hmm, I actually checked the docs for that because that would make
> .toggle an unsuitable overloader. The docs said toggle doesn't take
> arguments:
>

> Hmmm, indeed. :) Not so much outdated as incomplete. I just went ahead and
> added it to the docs:
> http://docs.jquery.com/Effects/toggle#speedcallback

Good :-) Anyway, that means no simple overloading method is available.
Of course it's no problem to code it or even to write a plugin, but I
thought overloading an existing function would make for an interesting
and probably often-used functionality, which was the point of starting
this thread.