(function($) {
	$.fn.lazyload = function(options) {
		var settings = {
			threshold: 0,
			failurelimit: 0,
			event: "scroll",
			effect: "show",
			container: window
		};
		if (options) {
			$.extend(settings, options);
		}
		var elements = this;
		if ("scroll" == settings.event) {
			$(settings.container).bind("scroll",
			function(event) {
				var counter = 0;
				elements.each(function() {
					if ($.abovethetop(this, settings) || $.leftofbegin(this, settings)) {} else if (!$.belowthefold(this, settings) && !$.rightoffold(this, settings)) {
						$(this).trigger("appear");
					} else {
						if (counter++>settings.failurelimit) {
							return false;
						}
					}
				});
				var temp = $.grep(elements,
				function(element) {
					return ! element.loaded;
				});
				elements = $(temp);
			});
		}
		this.each(function() {
			var self = this;
			if (undefined == $(self).attr("original")) {
				$(self).attr("original", $(self).attr("src"));
			}
			if ("scroll" != settings.event || undefined == $(self).attr("src") || "" == $(self).attr("src") || settings.placeholder == $(self).attr("src") || ($.abovethetop(self, settings) || $.leftofbegin(self, settings) || $.belowthefold(self, settings) || $.rightoffold(self, settings))) {
				if (settings.placeholder) {
					$(self).attr("src", settings.placeholder);
				} else {
					$(self).removeAttr("src");
				}
				self.loaded = false;
			} else {
				self.loaded = true;
			}
			$(self).one("appear",
			function() {
				if (!this.loaded || 1 == 1) {
					$("<img />").bind("load",
					function() {
						$(self).hide().attr("src", $(self).attr("original"))[settings.effect](settings.effectspeed);
						self.loaded = true;
					}).attr("src", $(self).attr("original"));
				};
			});
			if ("scroll" != settings.event) {
				$(self).bind(settings.event,
				function(event) {
					if (!self.loaded) {
						$(self).trigger("appear");
					}
				});
			}
		});
		$(settings.container).trigger(settings.event);
		return this;
	};
	$.belowthefold = function(element, settings) {
		if (settings.container === undefined || settings.container === window) {
			var fold = $(window).height() + $(window).scrollTop();
		} else {
			var fold = $(settings.container).offset().top + $(settings.container).height();
		}
		return fold <= $(element).offset().top - settings.threshold;
	};
	$.rightoffold = function(element, settings) {
		if (settings.container === undefined || settings.container === window) {
			var fold = $(window).width() + $(window).scrollLeft();
		} else {
			var fold = $(settings.container).offset().left + $(settings.container).width();
		}
		return fold <= $(element).offset().left - settings.threshold;
	};
	$.abovethetop = function(element, settings) {
		if (settings.container === undefined || settings.container === window) {
			var fold = $(window).scrollTop();
		} else {
			var fold = $(settings.container).offset().top;
		}
		return fold >= $(element).offset().top + settings.threshold + $(element).height();
	};
	$.leftofbegin = function(element, settings) {
		if (settings.container === undefined || settings.container === window) {
			var fold = $(window).scrollLeft();
		} else {
			var fold = $(settings.container).offset().left;
		}
		return fold >= $(element).offset().left + settings.threshold + $(element).width();
	};
	$.extend($.expr[':'], {
		"below-the-fold": "$.belowthefold(a, {threshold : 0, container: window})",
		"above-the-fold": "!$.belowthefold(a, {threshold : 0, container: window})",
		"right-of-fold": "$.rightoffold(a, {threshold : 0, container: window})",
		"left-of-fold": "!$.rightoffold(a, {threshold : 0, container: window})"
	});
})(jQuery);