Home >Web Front-end >JS Tutorial >Native js implements image carousel effects_javascript skills

Native js implements image carousel effects_javascript skills

WBOYOriginal: 2016-05-16 15:25:051895browse

This article specially summarizes the code for implementing image carousel effects in native js and shares it with everyone for your reference. Everyone is welcome to learn.

Operation rendering:

Specific code:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>最简单的轮播广告</title>
  <style>
    body, div, ul, li {
      margin: 0;
      padding: 0;
    }

    ul {
      list-style-type: none;
    }

    body {
      background: #000;
      text-align: center;
      font: 12px/20px Arial;
    }

    #box {
      position: relative;
      width: 492px;
      height: 172px;
      background: #fff;
      border-radius: 5px;
      border: 8px solid #fff;
      margin: 10px auto;
    }

    #box .list {
      position: relative;
      width: 490px;
      height: 170px;
      overflow: hidden;
      border: 1px solid #ccc;
    }

    #box .list li {
      position: absolute;
      top: 0;
      left: 0;
      width: 490px;
      height: 170px;
      opacity: 0;
      transition: opacity 0.5s linear
    }

    #box .list li.current {
      opacity: 1;
    }

    #box .count {
      position: absolute;
      right: 0;
      bottom: 5px;
    }

    #box .count li {
      color: #fff;
      float: left;
      width: 20px;
      height: 20px;
      cursor: pointer;
      margin-right: 5px;
      overflow: hidden;
      background: #F90;
      opacity: 0.7;
      border-radius: 20px;
    }

    #box .count li.current {
      color: #fff;
      opacity: 0.7;
      font-weight: 700;
      background: #f60
    }
  </style>
</head>
<body>
<div id="box">
  <ul class="list">
    <li class="current" style="opacity: 1;"><img src="img/images04/01.jpg" width="490" height="170"></li>
    <li style="opacity: 0;"><img src="img/images04/02.jpg" width="490" height="170"></li>
    <li style="opacity: 0;"><img src="img/images04/03.jpg" width="490" height="170"></li>
    <li style="opacity: 0;"><img src="img/images04/04.jpg" width="490" height="170"></li>
    <li style="opacity: 0;"><img src="img/images04/05.jpg" width="490" height="170"></li>
  </ul>
  <ul class="count">
    <li class="current">1</li>
    <li class="">2</li>
    <li class="">3</li>
    <li class="">4</li>
    <li class="">5</li>
  </ul>
</div>


<script>
  var box=document.getElementById('box');
  var uls=document.getElementsByTagName('ul');
  var imgs=uls[0].getElementsByTagName('li');
  var btn=uls[1].getElementsByTagName('li');
  var i=index=0; //中间量，统一声明；
  var play=null;
  console.log(box,uls,imgs,btn);//获取正确

  //图片切换, 淡入淡出效果我是用（transition: opacity 0.8s linear）做的,不纠结、简单 在css里面
  function show(a){        //方法定义的是当传入一个下标时，按钮和图片做出对的反应
    for(i=0;i<btn.length;i++ ){
      btn[i].className='';    //很容易看懂吧？每个按钮都先设置成看不见，然后把当前按钮设置成可见。
      btn[a].className='current';
    }
    for(i=0;i<imgs.length;i++){ //把图片的效果设置和按钮相同
      imgs[i].style.opacity=0;
      imgs[a].style.opacity=1;
    }
  }
  //切换按钮功能，响应对应图片
  for(i=0;i<btn.length;i++){
    btn[i].index=i;  //不知道你有没有发现，循环里的方法去调用循环里的变量体i，会出现调到的不是i的变动值的问题。所以我先在循环外保存住
    btn[i].onmouseover=function(){
      show(this.index);
      clearInterval(play); //这就是最后那句话追加的功能
    }
  }

  //自动轮播方法
function autoPlay(){
      play=setInterval(function(){ //这个paly是为了保存定时器的，变量必须在全局声明 不然其他方法调不到 或者你可以调用auto.play 也许可以但是没时间试了
      index++;
      index>=imgs.length&&(index=0);//可能有优先级问题，所以用了括号，没时间测试了。
      show(index);
    },1000)
  }
  autoPlay();//马上调用，我试过用window.onload调用这个方法，但是调用之后影响到了其他方法，使用autoPlay所以只能这样调用了

  //div的鼠标移入移出事件
  box.onmouseover=function(){
    clearInterval(play);
  };
  box.onmouseout=function(){
    autoPlay();
  };
  //按钮下标也要加上相同的鼠标事件，不然图片停止了，定时器没停，会突然闪到很大的数字上。 貌似我可以直接追加到之前定义事件中。

</script>
</body>
</html>

I hope this article will be helpful to everyone in learning javascript programming.

Statement：

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Previous article：Summary of ways to create objects in JavaScript (4 ways)_javascript skillsNext article：Summary of ways to create objects in JavaScript (4 ways)_javascript skills

See more

Native js implements image carousel effects_javascript skills

Related articles