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Example of using JS to implement image carousel

韦小宝

Jan 15, 2018 am 11:27 AM

javascriptpictureExample

The editor below will bring you an example of using JS to implement image carousel (front and back, end to end). The editor thinks it’s pretty good, so now I’ll share the js source code with you and give it as a reference. If you are interested in js, please follow the editor to take a look.

I have been to various interviews recently, and finally I was asked this question. My mind was confused. I didn’t know how to connect end to end at the time. I will study it after I come back. After a while, I finally got it. Without further ado, let’s just look at the code.

The code refers to someone who has already written the image carousel function (thank you again), but there is no end-to-end function. On this basis, I added the end-to-end function.

The effect is as follows:

<!DOCTYPE html>
<html>
<head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <title>图片轮播</title>
 <style type="text/css">
 body,p,ul,li,a,img{margin: 0;padding: 0;}
 ul,li{list-style: none;}
 a{text-decoration: none;}
 #wrapper{
  position: relative;
  margin: 30px auto; /* 上下边距30px，水平居中 */
  width: 400px;
  height: 200px;
 }
 #banner{
  position:relative;
  width: 400px;
  height: 200px;
  overflow: hidden;
 }
 .imgList{
  position:relative;
  width:2000px;
  height:200px;
  z-index: 10;
  overflow: hidden;
 }
 .imgList li{float:left;display: inline;}
 #prev,
 #next{
  position: absolute;
  top:80px;
  z-index: 20;
  cursor: pointer;
  opacity: 0.2;
  filter:alpha(opacity=20);
 }
 #prev{left: 10px;}
 #next{right: 10px;}
 #prev:hover,
 #next:hover{opacity: 0.5;filter:alpha(opacity=50);}

</style>
</head>
<body>
 <p id="wrapper"><!-- 最外层部分 -->
 <p id="banner"><!-- 轮播部分 -->
  <ul class="imgList"><!-- 图片部分 -->
  <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="/static/imghwm/default1.png"  data-src="./img/1.jpg"  class="lazy"      style="max-width:90%" height="200px" alt="1"></a></li>
  <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="/static/imghwm/default1.png"  data-src="./img/2.jpg"  class="lazy"      style="max-width:90%" height="200px" alt="2"></a></li>
  <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="/static/imghwm/default1.png"  data-src="./img/3.jpg"  class="lazy"      style="max-width:90%" height="200px" alt="3"></a></li>
  <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="/static/imghwm/default1.png"  data-src="./img/4.jpg"  class="lazy"      style="max-width:90%" height="200px" alt="4"></a></li>
  <li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><img src="/static/imghwm/default1.png"  data-src="./img/5.jpg"  class="lazy"      style="max-width:90%" height="200px" alt="5"></a></li>
 </ul>
 <img  src="/static/imghwm/default1.png"  data-src="./img/prev.png"  class="lazy"      style="max-width:90%" height="40px" id="prev" alt="Example of using JS to implement image carousel" >
 <img  src="/static/imghwm/default1.png"  data-src="./img/next.png"  class="lazy"      style="max-width:90%" height="40px" id="next" alt="Example of using JS to implement image carousel" >
</p>
</p>
<script type="text/javascript" src="./js/jquery-3.2.1.min.js"></script>
<script type="text/javascript">
var curIndex = 0, //当前index
 imgLen = $(".imgList li").length; //图片总数
$(".imgList").css("width", (imgLen+1)*400+"px");
// 定时器自动变换3秒每次
var autoChange = setInterval(function(){
 if(curIndex < imgLen-1){
  curIndex ++;
 }else{
  curIndex = 0;
 }
 //调用变换处理函数
 changeTo(curIndex);
},3000);

//左箭头滑入滑出事件处理
$("#prev").hover(function(){
 //滑入清除定时器
 clearInterval(autoChange);
}, function(){
 //滑出则重置定时器
 autoChangeAgain();
});

//左箭头点击处理
$("#prev").click(function(){
 //根据curIndex进行上一个图片处理
 // curIndex = (curIndex > 0) ? (--curIndex) : (imgLen - 1);
 if (curIndex == 0) {
  var element = document.createElement("li");
  element.innerHTML = $(".imgList li")[imgLen - 1].innerHTML;
  // $(".imgList li")[imgLen - 1].remove();
  $(".imgList").prepend(element);
  $(".imgList").css("left", -1*400+"px");
  changeTo(curIndex);
  curIndex = -1;
 } else if (curIndex == -1) {
  $(".imgList").css("left", -(imgLen-1)*400+"px");
  curIndex = imgLen-2;
  $(".imgList li")[0].remove();
  changeTo(curIndex);
 } else {
  --curIndex;
  changeTo(curIndex);
 }

});

//右箭头滑入滑出事件处理
$("#next").hover(function(){
 //滑入清除定时器
 clearInterval(autoChange);
}, function(){
 //滑出则重置定时器
 autoChangeAgain();
});
//右箭头点击处理
$("#next").click(function(){
 // curIndex = (curIndex < imgLen - 1) ? (++curIndex) : 0;
 console.log(imgLen);
 if (curIndex == imgLen-1) {
  var element = document.createElement("li");
  element.innerHTML = $(".imgList li")[0].innerHTML;
  // $(".imgList li")[0].remove();
  $(".imgList").append(element);
  ++curIndex;
 } else if (curIndex == imgLen) {
  curIndex = 0;
  $(".imgList").css("left", "0px");
  $(".imgList li")[imgLen].remove();
  curIndex++;
 } else {
  ++curIndex;
 }
 changeTo(curIndex);
});

//清除定时器时候的重置定时器--封装
function autoChangeAgain(){
 autoChange = setInterval(function(){
  if(curIndex < imgLen-1){
   curIndex ++;
  }else{
   curIndex = 0;
  }
 //调用变换处理函数
 changeTo(curIndex);
 },3000);
}


function changeTo(num){
 var goLeft = num * 400;
 $(".imgList").animate({left: "-" + goLeft + "px"},500);
}
</script>
</body>
</html>

The above example of using JS to implement image carousel is a small I have compiled all the content to share with you, I hope it can give you a reference! !

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