﻿(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);
