Penatalan halaman js asli melambatkan pemuatan kemahiran images

Penatalan halaman js asli melambatkan pemuatan kemahiran images_javascript

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Lepaskan： 2016-05-16 15:24:33

asal

1163 orang telah melayarinya

Contoh dalam artikel ini menerangkan kod aliran air terjun javascript, iaitu, penatalan halaman js tertunda memuatkan imej saya kongsikan dengan anda untuk rujukan anda Kod khusus adalah seperti berikut

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>原生Js页面滚动延迟加载图片</title>
<style type="text/css">
* 
{
 margin:0;
 padding:0
}
img.scrollLoading 
{
 border:1px solid #ccc;
 display:block;
 margin-top:10px;
}
</style>
</head>
<body>
<div id="content"></div>
</body>
</html>
<script type="text/javascript"> 
var _CalF = { 
 $:function(object){//选择器 
 if(object === undefined ) return; 
 var getArr = function(name,tagName,attr){ 
 var tagName = tagName || '*', 
 eles = document.getElementsByTagName(tagName), 
 clas = (typeof document.body.style.maxHeight === "undefined") &#63; "className" : "class";//ie6 
 attr = attr || clas, 
 Arr = []; 
 for(var i=0;i<eles.length;i++){ 
 if(eles[i].getAttribute(attr)==name){ 
 Arr.push(eles[i]); 
 } 
 } 
 return Arr; 
 }; 
 if(object.indexOf('#') === 0){ //#id 
 return document.getElementById(object.substring(1)); 
 }
 else if(object.indexOf('.') === 0){ //.class 
 return getArr(object.substring(1)); 
 }
 else if(object.match(/=/g)){ //attr=name
 return getArr(object.substring(object.search(/=/g)+1),null,object.substring(0,object.search(/=/g))); 
 }
 else if(object.match(/./g)){ //tagName.className 
 return getArr(object.split('.')[1],object.split('.')[0]); 
 } 
 }, 
 getPosition : function(obj) { //获取元素在页面里的位置和宽高 
 var top = 0, 
 left = 0, 
 width = obj.offsetWidth, 
 height = obj.offsetHeight; 
 while(obj.offsetParent){ 
 top += obj.offsetTop; 
 left += obj.offsetLeft; 
 obj = obj.offsetParent; 
 } 
 return {"top":top,"left":left,"width":width,"height":height}; 
 } 
}; 
 
//添加图片list 
var _temp = []; 
for (var i = 1; i < 21; i ++) { 
 _temp.push('<img class="scrollLoading" data-src="http://images.cnblogs.com/cnblogs_com/Darren_code/311197/o_' + i + '.jpg" src="http://images.cnitblog.com/blog/150659/201306/23160223-c81dd9aa9a2a4071a47b0ced2c9118bc.gif" /><br />图片' + i); 
} 
_CalF.$("#content").innerHTML = _temp.join(""); 
 
function scrollLoad(){ 
 this.init.apply(this, arguments); 
} 
scrollLoad.prototype ={ 
 init : function(className){ 
 var className = "img."+className, 
 imgs = _CalF.$(className), 
 that = this; 
 this.imgs = imgs; 
 that.loadImg(); 
 window.onscroll = function(){ 
 that.time = setTimeout(function(){ 
 that.loadImg(); 
 },400); 
 } 
}, 
loadImg : function(){ 
var imgs = this.imgs.reverse(), //获取数组翻转 
len = imgs.length; 
if(imgs.length===0){ 
 clearTimeout(this.time); 
 return; 
} 
for(var j=len-1;j>=0;j--){ //递减 
 var img = imgs[j], 
 imgTop = _CalF.getPosition(img).top, 
 imgSrc = img.getAttribute("data-src"), 
 offsetPage = window.pageYOffset &#63; window.pageYOffset : window.document.documentElement.scrollTop,//滚动条的top值 
 bodyHeight = document.documentElement.clientHeight; //body的高度 
 if((offsetPage+bodyHeight/2) > (imgTop-bodyHeight/2)){ 
 img.src = imgSrc; 
 this.imgs.splice(j,1); 
 } 
 } 
 } 
} 
 
var img1 = new scrollLoad("scrollLoading"); 
</script>

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