Magento的速度是令人头疼的问题，我现在介绍一种前端的加速方法。说到lazyload,相信很多人都不陌生，现在很多网站都已经用到这个技术，他可以延迟加载长页面的图片。对于Magento这样的商城网站的加速就很明显了。我今天说的这个lazyload是经过POPO改造的（强逼我给他加外连……）。下面我放一些测试的数据，我正在做的一个网站的列表页。
很明显的就能看出差距。接下来写下用法：
首先加上jQuery,lazyload两段js。
lazyload：
(function($) {
$.fn.lazyload = function(options) {
var settings = {
threshold : 0,
failurelimit : 0,
event : "scroll",
effect : "show",
container : window
};
if(options) {
$.extend(settings, options);
}
/* Fire one scroll event per scroll. Not one scroll event per image. */
var elements = this;
if ("scroll" == settings.event) {
$(settings.container).bind("scroll", function(event) {
var counter = 0;
elements.each(function() {
if ($.abovethetop(this, settings) ||
$.leftofbegin(this, settings)) {
/* Nothing. */
} else if (!$.belowthefold(this, settings) &&
!$.rightoffold(this, settings)) {
$(this).trigger("appear");
} else {
if (counter++ > settings.failurelimit) {
return false;
}
}
});
/* Remove image from array so it is not looped next time. */
var temp = $.grep(elements, function(element) {
return !element.loaded;
});
elements = $(temp);
});
}
this.each(function() {
var self = this;
/* When appear is triggered load original image. */
$(self).one("appear", function() {
if (!this.loaded) {
$("<img alt="" />")
.bind("load", function() {
$(self)
.hide()
.attr("src", $(self).attr("original"))
[settings.effect](settings.effectspeed);
self.loaded = true;
})
.attr("src", $(self).attr("original"));
};
});
/* When wanted event is triggered load original image */
/* by triggering appear. */
if ("scroll" != settings.event) {
$(self).bind(settings.event, function(event) {
if (!self.loaded) {
$(self).trigger("appear");
}
});
}
});
/* Force initial check if images should appear. */
$(settings.container).trigger(settings.event);
return this;
};
/* Convenience methods in jQuery namespace. */
/* Use as $.belowthefold(element, {threshold : 100, container : window}) */
$.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();
};
/* Custom selectors for your convenience. */
/* Use as $("img:below-the-fold").something() */
$.extend($.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})"
});
$(function(){
$("img[original]").lazyload({
threshold : 200,effect: "fadeIn"
});
});
})(jQuery);
然后修改图片的路径
例如：<img alt=”" src=”<?php echo $this->getSkinUrl(‘images/co.jpg’) ?>”/>
修改为<img alt=”" original=”<?php echo $this->getSkinUrl(‘images/co.jpg’) ?>” src=”……”/>。
后面这个src里的图片是一个1像素的透明gif图片。
这样就可以了，有兴趣的可以尝试下。
原文链接地址：http://www.magentofront-end.com/magentomuban/232