(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") || 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) $("<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)