详情案例可参看本网站改造后的效果,目前覆盖首页、栏目页、内容页界面。
核心JS代码:
<script type="text/javascript"> var fgm = { on: function(element, type, handler) { return element.addEventListener ? element.addEventListener(type, handler, false) : element.attachEvent("on" + type, handler) }, bind: function(object, handler) { return function() { return handler.apply(object, arguments) } }, pageX: function(element) { return element.offsetLeft + (element.offsetParent ? arguments.callee(element.offsetParent) : 0) }, pageY: function(element) { return element.offsetTop + (element.offsetParent ? arguments.callee(element.offsetParent) : 0) }, hasClass: function(element, className) { return new RegExp("(^|\s)" + className + "(\s|$)").test(element.className) }, attr: function(element, attr, value) { if(arguments.length == 2) { return element.attributes[attr] ? element.attributes[attr].nodeValue : undefined } else if(arguments.length == 3) { element.setAttribute(attr, value) } } }; //延时加载 function LazyLoad(obj) { this.lazy = typeof obj === "string" ? document.getElementById(obj) : obj; this.aImg = this.lazy.getElementsByTagName("img"); this.fnLoad = fgm.bind(this, this.load); this.load(); fgm.on(window, "scroll", this.fnLoad); fgm.on(window, "resize", this.fnLoad); } LazyLoad.prototype = { load: function() { var iScrollTop = document.documentElement.scrollTop || document.body.scrollTop; var iClientHeight = document.documentElement.clientHeight + iScrollTop; var i = 0; var aParent = []; var oParent = null; var iTop = 0; var iBottom = 0; var aNotLoaded = this.loaded(0); if(this.loaded(1).length != this.aImg.length) { for(i = 0; i < aNotLoaded.length; i++) { oParent = aNotLoaded[i].parentElement || aNotLoaded[i].parentNode; iTop = fgm.pageY(oParent); iBottom = iTop + oParent.offsetHeight; if((iTop > iScrollTop && iTop < iClientHeight) || (iBottom > iScrollTop && iBottom < iClientHeight)) { aNotLoaded[i].src = fgm.attr(aNotLoaded[i], "data-img") || aNotLoaded[i].src; aNotLoaded[i].className = "loaded"; } } } }, loaded: function(status) { var array = []; var i = 0; for(i = 0; i < this.aImg.length; i++) eval("fgm.hasClass(this.aImg[i], "loaded")" + (!!status ? "&&" : "||") + "array.push(this.aImg[i])"); return array } }; //应用添加 fgm.on(window, "load", function () {new LazyLoad("box")}); fgm.on(window, "load", function () {new LazyLoad("bxslider")}); </script>
在添加JS后直接在应用添加里面添加对应需要执行懒加载的区域即可,图片的代码调整为<img data-img="XXX"/>
内容页需要执行懒加载的话,参考:《dede手机站调用PC站图片》中函数的使用方法即可。需要帮助调整的,可在百家号贤话师兄处关注留言。