Very simple jQuery event for handling unfocusing of elements when clicking outside of them.

jquery.clickoutside.js

(function($) {

var WATCH_FOCUS_ON = $();

$.event.special['clickoutside'] = {
	setup: function()
	{
		WATCH_FOCUS_ON = WATCH_FOCUS_ON.add( this );

		// bind document handler if this is the first guy being bound
		if ( WATCH_FOCUS_ON.length === 1 ) {
			$(document).bind( 'click.clickoutside', unfocusHandler );
		}
	},
	teardown: function()
	{
		WATCH_FOCUS_ON = WATCH_FOCUS_ON.not(this);

		// unbind document handler when last one removed
		if ( WATCH_FOCUS_ON.length === 0 ) {
			$(document).unbind( 'click.clickoutside' );
		}
	},
	add: function(handleObj)
	{
		var old_handler = handleObj.handler;

		// override default event.target reference with one that is applicable
		handleObj.handler = function(event, elem) {
			event.target = WATCH_FOCUS_ON;
			old_handler.apply(this, arguments);
		};
	}
};

function unfocusHandler(event)
{
	$(WATCH_FOCUS_ON).each(function() {
		var elem = $(this);

		// clicked, but not on this element and not inside it. Fire stuff.
		if (this !== event.target && !elem.has(event.target).length) {
			elem.triggerHandler('clickoutside', [event.target]);
		}
	});
};

})(jQuery);