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opencart是一个PHP开源商城系统,商城系统一般会使用大量的图片来装饰网站,那么,网站的加载时间会很长。有什么办法能提高opencart的打开速度呢?除了开启GZIP压缩和图片本身的大小控制之外,我们还可以利用图片延迟加载。
在頁腳加入兩段JS代碼:
第一段:
<script type="text/javascript">
$(function() {
$(".image img,.banner img,.tab-content img").lazyload({
effect:"fadeIn",
failurelimit : 30
});
});
</script>
其中,第三行这里,我是根据自己网站模板来取得相关的值,第一个.image img 这个是商品分类图片的img图片的div定位,多个用英文半角逗号隔开!比如.banner img 这个是广告图片那个地方的,第三个则是产品详情页正文地方的!当然了,你的模板可以自己去定位下,修改第三行这里,其他不用更改啦。
第二段代码比较长,建议新建个JS文件,放文件里面,然后引用过来。
(function($) {
$.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) {
$(settings.container).bind("scroll",
function(event) {
var counter = 0;
elements.each(function() {
if (!$.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)
})
}
return this.each(function() {
var self = this;
$(self).attr("original", $(self).attr("src"));
if ("scroll" != settings.event || $.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")
}
})
}
})
};
$.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
};
$.extend($.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);
用下面的代码引用JS
<script type="text/javascript" src="xxx/js/lazyload.js"></script>
然後上傳相關的JS文件和寫入代碼到頁腳,也就是footer.tpl
好了,然後看效果就知道了。 |
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