The simplest JavaScript image carousel code (two methods)

The simplest JavaScript image carousel code (two methods)_javascript skills

WBOY

Release： 2016-05-16 15:24:43

Original

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By changing the opacity attribute of each image:

Material picture:

Code 1:

<!DOCTYPE html>
 <html lang="en">
 <head>
  <meta charset="UTF-">
  <title>最简单的轮播广告</title>
  <style>
   body, div, ul, li {
    margin: ;
    padding: ;
   }
   ul {
    list-style-type: none;
   }
   body {
    background: #;
    text-align: center;
    font: px/px Arial;
   }
   #box {
    position: relative;
    width: px;
    height: px;
    background: #fff;
    border-radius: px;
    border: px solid #fff;
    margin: px auto;
   }
   #box .list {
    position: relative;
    width: px;
    height: px;
    overflow: hidden;
    border: px solid #ccc;
   }
   #box .list li {
    position: absolute;
    top: ;
    left: ;
    width: px;
    height: px;
    opacity: ;
    transition: opacity .s linear
   }
   #box .list li.current {
    opacity: ;
   }
   #box .count {
    position: absolute;
    right: ;
    bottom: px;
   }
   #box .count li {
    color: #fff;
    float: left;
    width: px;
    height: px;
    cursor: pointer;
    margin-right: px;
    overflow: hidden;
    background: #F;
    opacity: .;
    border-radius: px;
   }
   #box .count li.current {
    color: #fff;
    opacity: .;
    font-weight: ;
    background: #f
   }
  </style>
 </head>
 <body>
 <div id="box">
  <ul class="list">
   <li class="current" style="opacity: ;"><img src="img/images/.jpg" width="" height=""></li>
   <li style="opacity: ;"><img src="img/images/.jpg" width="" height=""></li>
   <li style="opacity: ;"><img src="img/images/.jpg" width="" height=""></li>
   <li style="opacity: ;"><img src="img/images/.jpg" width="" height=""></li>
   <li style="opacity: ;"><img src="img/images/.jpg" width="" height=""></li>
  </ul>
  <ul class="count">
   <li class="current"></li>
   <li class=""></li>
   <li class=""></li>
   <li class=""></li>
   <li class=""></li>
  </ul>
 </div>
 <script>
  var box=document.getElementById('box');
  var uls=document.getElementsByTagName('ul');
  var imgs=uls[].getElementsByTagName('li');
  var btn=uls[].getElementsByTagName('li');
  var i=index=; //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 .s 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=;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=;i<imgs.length;i++){ //把图片的效果设置和按钮相同
    imgs[i].style.opacity=;
    imgs[a].style.opacity=;
   }
  }
  //切换按钮功能，响应对应图片
  for(i=;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=);//可能有优先级问题，所以用了括号，没时间测试了。
    show(index);
   },)
  }
  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>

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Code 2:

The first step is to download a jquery library plug-in. jquery.js can be downloaded from many places on the Internet. The downloaded plug-in should be placed in the directory. Then link

in the html document

The second step is to lay out a DIV, such as:

<div id="scroll">
 <p class="subl">上一张<p/>
 <p class="subr">下一张<p/>
 <ul>
 <li style="background:red;display:block;"></li>
　//上面的ｌｉ要设定为显示，因为是第一张图片．
 <li style="background:green;"></li>
 <li style="background:gray;"></li>
 <li style="background:orange;"></li>
 </ul>
 </div>

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In order to make it easier for netizens to download clearly, I did not use the image path, because it will not be visible on your computer. Here I use the background color.

The third step is to write CSS. Anyone who knows the basics of CSS can understand the following CSS.

#scroll{width:100%; height:180px; background-color:white; position:relative;border-bottom:1px solid gray;}//这里是给整个大的ＤＩＶ设定属性．
#scroll ul{height:180px; list-style:none;}//ＤＩＶ下的ＵＬ属性．
#scroll ul li{width:100%; height:180px;margin:0px; padding:0px; display:none;}//ＤＩＶ下的ＵＬ下的ＬＩ属性．注意：display:none;因为要将所有的ｌｉ隐藏了先．当点击的时候在显示出来．
 .subl{position:absolute; bottom:20px; left:40%; width:80px;height:20px; line-height:20px; text-align:center;font-size:16px;font-weight:bold; cursor:pointer;}//上一张按钮的属性．注意一个绝对定位．
 .subr{
position:absolute;
bottom:20px; right:40%;
width:80px;height:20px; line-height:20px; text-align:center;font-size:16px;font-weight:bold;cursor:pointer; 
}//下一张按钮的属性．注意一个绝对定位．
.subr:hover{ background:yellow;border-radius:10px;}
.subl:hover{ background:yellow;border-radius:10px;}
//以上两个hover是鼠标经过的效果．

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The fourth step is the jｑuery code! It's also very simple. Read the code first and you will be able to use it!

<script type="text/javascript">
/*轮播*/
 $(function(){
 var i=0;
 var len=$("#scroll ul li").length-1;
 $(".subl").click(function(){
 if(i==len){
i=-1;
}
i++;
$("#scroll ul li").eq(i).fadeIn().siblings().hide();
 });
//到这里分开！上面的是上一张点击的效果代码，下面的是下一张点击的效果代码．
 $(".subr").click(function(){//获取类名的点击事件．
 if(i==0){
i=len+1;
}
i--;
$("#scroll ul li").eq(i).fadeIn().siblings().hide();
 });
 });
 /*轮播*/
</script>

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Four easy steps to make a simple wheel!