js实现多张图片延迟加载效果

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我是靠谱客的博主多情夏天，这篇文章主要介绍js实现多张图片延迟加载效果，现在分享给大家，希望可以做个参考。

本文实例为大家分享了js实现多张图片延迟加载效果的具体代码，供大家参考，具体内容如下

具体代码如下:

复制代码

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  
  <meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport">
  <title>Document</title>
  <style>
    *{
      margin:0;
      padding:0;
      font-size:14px;
    }
    ul,li{
      list-style:none;
    }
    img{
      display:block;
      border:none;
    }
    /*
      最外层容器不设定宽高的
    */
    .news{
      padding:10px;
    }
    .news li{
      height:60px;
      padding:10px 0;
      border-bottom:1px solid #dedede;
      position:relative;
    }
    .news li > div:nth-child(1){
      position:absolute;
      top:10px;
      left:0;
      width:75px;
      height:60px;
      background:url('img/default.png') no-repeat center center;
      background-size:100% 100%;/*设置背景图片大小*/
    }
    .news li > div:nth-child(1) img{
      width:100%;
      height:100%;
      display:none;
      opacity:0;
    }
    .news li > div:nth-child(2){
      height:60px;
      margin-left:80px;
    }
    .news li > div:nth-child(2) h2{
      height:20px;
      line-height:20px;
      /*实现文字超出隐藏*/
      overflow:hidden;
      text-overflow:ellipsis;
      white-space: nowrap;
    }
    .news li > div:nth-child(2) p{
      line-height:20px;
      font-size:12px;
      color:#ccc;
    }
  </style>
</head>
<body>
  <ul id='news' class='news'>
    <li>
      <div>
        <img src="" alt="">
      </div>
      <div>
        <h2>我是一个标题</h2>
        <p>我是内容</p>
      </div>
    </li>
  </ul>

function fadeIn(curImg){
      var duration = 500,interval = 10,target = 1;
      var step = (target/duration)*interval;
      var timer = window.setInterval(function(){
        var curOP = utils.getCss(curImg,'opacity');
        if(curOP>1){
          curImg.style.opacity = 1;
          window.clearInterval(timer)
          return
        }
        curOP+=step;
        curImg.style.opacity = curOP;
      },interval)

}

//4、开始的时候一秒加载第一屏的图片，当滚动条滚动的时候，再加载剩余的图片
    window.setTimeout(handleAllImage,1000);
    window.onscroll = handleAllImage;
  </script>
</body>
</html>

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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <!--做移动端响应式必须加的样式-->
  <meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport">
  <title>Document</title>
  <style>
    *{
      margin:0;
      padding:0;
      font-size:14px;
    }
    ul,li{
      list-style:none;
    }
    img{
      display:block;
      border:none;
    }
    /*
      最外层容器不设定宽高的
    */
    .news{
      padding:10px;
    }
    .news li{
      height:60px;
      padding:10px 0;
      border-bottom:1px solid #dedede;
      position:relative;
    }
    .news li > div:nth-child(1){
      position:absolute;
      top:10px;
      left:0;
      width:75px;
      height:60px;
      background:url('img/default.png') no-repeat center center;
      background-size:100% 100%;/*设置背景图片大小*/
    }
    .news li > div:nth-child(1) img{
      width:100%;
      height:100%;
      display:none;
      opacity:0;
    }
    .news li > div:nth-child(2){
      height:60px;
      margin-left:80px;
    }
    .news li > div:nth-child(2) h2{
      height:20px;
      line-height:20px;
      /*实现文字超出隐藏*/
      overflow:hidden;
      text-overflow:ellipsis;
      white-space: nowrap;
    }
    .news li > div:nth-child(2) p{
      line-height:20px;
      font-size:12px;
      color:#ccc;
    }
  </style>
</head>
<body>
  <ul id='news' class='news'>
    <li>
      <div>
        <img src="" alt="">
      </div>
      <div>
        <h2>我是一个标题</h2>
        <p>我是内容</p>
      </div>
    </li>
  </ul>

  <script>
    var news = document.getElementById('news')
    var imgList = news.getElementsByTagName('img')
    //1、获取需要绑定的数据（Ajax）
    var jsonData = null;
    ~function(){
      var xhr = new XMLHttpRequest();
      //URL地址后面加的随机数是在清除每一次请求数据时候（GET请求）产生的缓存
      xhr.open('GET','data.json?_='+Math.random(),false)
      xhr.onreadystatechange = function(){
        if(xhr.readystate ===4 && /^2d{2}$/.test(xhr.status)){
          var val = xhr.responseText;
          jsonData = utils.formatJSON(val)
        }
      }
      xhr.send(null)
    }()
    //2、数据绑定->把jsonData存储的数据绑定到页面中（字符串拼接）
    ~function(){
      var str = '';
      if(jsonData){
        for(var i = 0,len = jsonData.length;i<len;i++){
          var curData = jsonData[i]
          str+='<li>';
          str+='<div><img src="" trueImg="'+curData['img']+'"></div>';
          str+='<div>';
          str+='<h2>'+curData['title']+'</h2>';
          str+='<p>'+curData['desc']+'</p>';
          str+='</div>';
          str+='</li>';
        }
      }
      news.innerHTML = str;
    }()
    //3、图片延迟加载
    //我先编写一个方法实现单张图片的延迟加载
    function lazyImg(curImg){
      var oImg = new Image;
      oImg.src = curImg.getAttribute('trueImg');
      oImg.onload = function(){
        curImg.src = this.src;
        curImg.style.display = "block";
        fadeIn(curImg)
        oImg = null
      };
      curImg.isLoad = true;
    }

    function fadeIn(curImg){
      var duration = 500,interval = 10,target = 1;
      var step = (target/duration)*interval;
      var timer = window.setInterval(function(){
        var curOP = utils.getCss(curImg,'opacity');
        if(curOP>1){
          curImg.style.opacity = 1;
          window.clearInterval(timer)
          return
        }
        curOP+=step;
        curImg.style.opacity = curOP;
      },interval)

    }

    function handleAllImage(){
      for(var i = 0,len = imgList.length;i<len;i++){
        var curImg = imgList[i];
        //当前的图片处理过了就不需要在重新的进行处理了
        if(curImg.isLoad = true){
          continue;
        }
        //只有A小于B的时候才进行处理,当前图片是隐藏的，我们其实计算的是它父节点的A
        var curImgPar = curImg.parentNode;
        var A = utils.offset(curImgPar).top + curImgPar.offsetHeight;
        var B = utils.win('clientHeight')+utils.win('scrollTop');
        if(A<B){
          lazyImg(curImg);
        }
      }
    }

    //4、开始的时候一秒加载第一屏的图片，当滚动条滚动的时候，再加载剩余的图片
    window.setTimeout(handleAllImage,1000);
    window.onscroll = handleAllImage;
  </script>
</body>
</html>