jQuery offscreen plugin

jquery.offscreen.js

/*
 * jQuery offscreen plugin
 *
 * Filters that detect when an element is partially or completely outside 
 * of the viewport.
 *
 *	Usage:
 *
 *		$('#element').is(':off-bottom')
 *
 * The above example returns true if #element's bottom edge is even 1px past 
 * the bottom part of the viewport.
 *
 * Copyright Cory LaViska for A Beautiful Site, LLC. (http://www.abeautifulsite.net/)
 *
 * Licensed under the MIT license: http://opensource.org/licenses/MIT
 *
*/
(function($) {
	$.extend($.expr[':'], {
		'off-top': function(el) {
			return $(el).offset().top < $(window).scrollTop();
		},
		'off-right': function(el) {
			return $(el).offset().left + $(el).outerWidth() - $(window).scrollLeft() > $(window).width();
		},
		'off-bottom': function(el) {
			return $(el).offset().top + $(el).outerHeight() - $(window).scrollTop() > $(window).height();
		},
		'off-left': function(el) {
			return $(el).offset().left < $(window).scrollLeft();
		}
	});
})(jQuery);

This is handy!

Moved to repo: https://github.com/claviska/jquery-offscreen