Native js implements image carousel effects_javascript skills-JS Tutorial-php.cn

Home

Web Front-end

JS Tutorial

Native js implements image carousel effects_javascript skills

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

May 16, 2016 pm 03:25 PM

jsImage Carousel

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="/static/imghwm/default1.png"  data-src="img/images04/01.jpg"  class="lazy"    style="max-width:90%"  style="max-width:90%" alt="Native js implements image carousel effects_javascript skills" ></li>
    <li style="opacity: 0;"><img  src="/static/imghwm/default1.png"  data-src="img/images04/02.jpg"  class="lazy"    style="max-width:90%"  style="max-width:90%" alt="Native js implements image carousel effects_javascript skills" ></li>
    <li style="opacity: 0;"><img  src="/static/imghwm/default1.png"  data-src="img/images04/03.jpg"  class="lazy"    style="max-width:90%"  style="max-width:90%" alt="Native js implements image carousel effects_javascript skills" ></li>
    <li style="opacity: 0;"><img  src="/static/imghwm/default1.png"  data-src="img/images04/04.jpg"  class="lazy"    style="max-width:90%"  style="max-width:90%" alt="Native js implements image carousel effects_javascript skills" ></li>
    <li style="opacity: 0;"><img  src="/static/imghwm/default1.png"  data-src="img/images04/05.jpg"  class="lazy"    style="max-width:90%"  style="max-width:90%" alt="Native js implements image carousel effects_javascript skills" ></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

Understanding the JavaScript Engine: Implementation DetailsApr 17, 2025 am 12:05 AM

Understanding how JavaScript engine works internally is important to developers because it helps write more efficient code and understand performance bottlenecks and optimization strategies. 1) The engine's workflow includes three stages: parsing, compiling and execution; 2) During the execution process, the engine will perform dynamic optimization, such as inline cache and hidden classes; 3) Best practices include avoiding global variables, optimizing loops, using const and lets, and avoiding excessive use of closures.

Python vs. JavaScript: The Learning Curve and Ease of UseApr 16, 2025 am 12:12 AM

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

Python vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AM

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

From C/C to JavaScript: How It All WorksApr 14, 2025 am 12:05 AM

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

JavaScript Engines: Comparing ImplementationsApr 13, 2025 am 12:05 AM

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

Beyond the Browser: JavaScript in the Real WorldApr 12, 2025 am 12:06 AM

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.

Building a Multi-Tenant SaaS Application with Next.js (Backend Integration)Apr 11, 2025 am 08:23 AM

I built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing

How to Build a Multi-Tenant SaaS Application with Next.js (Frontend Integration)Apr 11, 2025 am 08:22 AM

This article demonstrates frontend integration with a backend secured by Permit, building a functional EdTech SaaS application using Next.js. The frontend fetches user permissions to control UI visibility and ensures API requests adhere to role-base

See all articles