JS實作圖片無序預載功能碼-js教程-PHP中文網

JS實作圖片無序預載功能碼

零下一度

發布： 2017-05-13 11:00:50

原創

1355 人瀏覽過

這篇文章主要介紹了JS實現圖片預加載之無序預加載功能代碼,非常不錯，具有參考借鑒價值，需要的朋友可以參考下

圖片預先載入之無序預先載入的效果圖如下圖所示，如果大家感覺不錯，請參考實作程式碼。

具體程式碼如下：

<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <title>PreLoading</title>
  <style>
    *{margin:0; padding:0; border:none; outline:0; text-decoration:none;}
    html,body,.box{width:100%; height:100%;}
    .box{display:none;}
    #img{width:90%; height:90%; margin:2vh auto 0; display:block; box-shadow:0 0 10px gray;}
    .box .btns{width:140px; height:40px; display:block; margin:20px auto;}
    .box .btns .btn{width:60px; height:40px; display:block; border:1px gray solid; background-color:#ccc; text-align:center; line-height:40px; float:left;}
    .box .btns .btn:nth-of-type(2){margin-left:16px;}
    .load{width:100%; height:100%; display:block; font-size:60px; font-family:"微软雅黑"; color:#ccc; text-align:center; line-height:100vh; position:fixed;}
  </style>
</head>
<body>
  <p class="box">
    <img id="img" src="" alt="pic">
    <p class="btns"><a href="javascript:" rel="external nofollow" rel="external nofollow" class="btn">prev</a><a href="javascript:" rel="external nofollow" rel="external nofollow" class="btn">next</a></p>
  </p>
  <p class="load">0%</p>
  <script type="text/javascript">
    var imgs = [&#39;http://down.699pic.com/photo/50036/7661.jpg?_upt=da51378d1494571758&_upd=500367661.jpg&#39;,
          &#39;http://desk.fd.zol-img.com.cn/t_s1920x1080c5/g5/M00/09/0F/ChMkJljskIqIPX9bAAMPyuIn8DcAAbj8QB7XpYAAw_i343.jpg&#39;,
          &#39;http://desk.fd.zol-img.com.cn/t_s1920x1080c5/g5/M00/09/0F/ChMkJljskLeIaW-JAAIudN_yqvgAAbj8gDQO5AAAi6M64.jpeg&#39;,
          &#39;http://desk.fd.zol-img.com.cn/t_s1920x1080c5/g5/M00/0F/08/ChMkJlauzISIH0uXAARUHuJLVX8AAH8-gHu6zsABFQ2166.jpg&#39;,
          &#39;http://desk.fd.zol-img.com.cn/t_s1920x1080c5/g5/M00/0F/08/ChMkJlauzISIIL5TAAObxg4-XeUAAH8-gHzP3EAA5ve000.jpg&#39;];
    // 绑定按钮事件
    var btns = document.getElementsByClassName(&#39;btn&#39;),
      img = document.getElementById(&#39;img&#39;),
      index = 0;
    for(var i=0;i<btns.length;i++){
      btns[i].onclick = function(){
        if(this.innerHTML === &#39;next&#39;){
          index = Math.min(++index , imgs.length-1);
          img.setAttribute(&#39;src&#39;,imgs[index]);
        }
        if(this.innerHTML === &#39;prev&#39;){
          index = Math.max(--index , 0);
          img.setAttribute(&#39;src&#39;,imgs[index]);
        }
      }
    }
    // 计数变量
    var count = 0,
      load = document.getElementsByClassName(&#39;load&#39;)[0],
      box = document.getElementsByClassName(&#39;box&#39;)[0];
    // 无序预加载
    for(var i=0;i<imgs.length;i++){
      (function(i){
        var imgObj = new Image();
      imgObj.onload = function(){
          load.innerHTML = Math.round((count + 1) / imgs.length * 100) + &#39;%&#39;;
          count++;
          if(count >= imgs.length-1){
            load.style.display = &#39;none&#39;;
            box.style.display = &#39;block&#39;;
            img.setAttribute(&#39;src&#39;,imgs[0]);
            document.title = &#39;1/&#39; + imgs.length;
          }
        }
      imgObj.onerror = function(){
          load.innerHTML = Math.round((count + 1) / imgs.length * 100) + &#39;%&#39;;
          count++;
          if(count >= imgs.length-1){
            load.style.display = &#39;none&#39;;
            box.style.display = &#39;block&#39;;
            img.setAttribute(&#39;src&#39;,imgs[0]);
            document.title = &#39;1/&#39; + imgs.length;
          }
        }
        imgObj.src = imgs[i];
      })(i);
    }
  </script>
</body>
</html>

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