轮播图在前端开发中我认为是一个比较重要的点,因为包含了很多原生js知识点,以下是我学习制作轮播图的过程
难点:
1、如何让底下圆圈和图片所对应自动动态生成
2、如何让底下圆圈和图片所对应的起来
3、上一页和下一页所在盒子所移动的距离
4、图片切换时的渐出动画效果
5、节流阀的概念
效果:
代码:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <style> * { padding: 0; margin: 0; } a { text-decoration: none; color: white; line-height: 50px; text-align: center; } li { list-style: none; } .tb-promo { position: relative; width: 700px; height: 300px; margin: auto; overflow: hidden; } .tb-promo .imgg { position: absolute; top: 0; left: 0; width: 3000px; } .tb-promo .imgg li { float: left; } .tb-promo .imgg li img { width: 700px; height: 300px; } .tb-promo .prev { display: none; position: absolute; top: 125px; left: 0; width: 25px; height: 50px; background-color: rgba(0, 0, 0, 0.2); border-top-right-radius: 25px; border-bottom-right-radius: 25px; z-index: 999; } .tb-promo .prev:hover { background-color: rgba(0, 0, 0, 0.5); } .tb-promo .next { display: none; position: absolute; top: 125px; right: 0; width: 25px; height: 50px; background-color: rgba(0, 0, 0, 0.2); border-top-left-radius: 25px; border-bottom-left-radius: 25px; z-index: 999; } .tb-promo .next:hover { background-color: rgba(0, 0, 0, 0.5); } .tb-promo .promo-nav { position: absolute; top: 270px; left: 50%; margin-left: -40px; height: 25px; } .tb-promo .promo-nav li { float: left; width: 16px; height: 16px; background-color: white; border-radius: 8px; margin: 4px; } .tb-promo .promo-nav .one { background-color: tomato; } </style> </head> <body> <div class="tb-promo"> <a href="javascript:;" class="prev"><</a> <a href="javascript:;" class="next">></a> <ul class="imgg"> <li><img src="./61.jpeg" alt=""></li> <li><img src="./62.jpeg" alt=""></li> <li><img src="./63.jpeg" alt=""></li> </ul> <ol class="promo-nav"> </ol> </div> <script> var prev = document.querySelector('.prev'); var next = document.querySelector('.next'); var tbpromo = document.querySelector('.tb-promo'); var ul = document.querySelector('ul'); var ol = document.querySelector('ol'); //动画函数 function animate(obj, target) { clearInterval(obj.timer);//调用防止点击多次调用 obj.timer = setInterval(function () { var step = (target - obj.offsetLeft) / 10; step = step > 0 ? Math.ceil(step) : Math.floor(step); //正直和负值取整 if (obj.offsetLeft == target) { clearInterval(obj.timer); } else { obj.style.left = obj.offsetLeft + step + 'px'; } }, 10) } //生成动态导航圈圈 var tbpromWidth = tbpromo.offsetWidth; for (var i = 0; i < ul.children.length; i++) { var li = document.createElement('li'); ol.appendChild(li); //记录索引号 通过自定义属性 li.setAttribute('index', i); //排他思想 写圆圈变色 li.addEventListener('click', function () { //清除所有圈圈颜色 for (var i = 0; i < ol.children.length; i++) { ol.children[i].className = ''; } this.className = 'one'; var index = this.getAttribute('index'); //点击li 把li 的索引号分别给控制变量 num = index; circle=index; animate(ul, -index * tbpromWidth); }) ol.children[0].className = 'one'; } //克隆第一张图片li放在最后面 无缝切换 var frist = ul.children[0].cloneNode(true); ul.appendChild(frist); //隐藏显示 下一页上一页 tbpromo.addEventListener('mouseenter', function () { prev.style.display = 'block'; next.style.display = 'block'; clearInterval(timer); timer=0;//清除定时器变量 }) tbpromo.addEventListener('mouseleave', function () { prev.style.display = 'none'; next.style.display = 'none'; timer=setInterval(function () { next.click();//手动调动点击事件 },1500) }) //next prev动画 var num = 0; //控制圆圈 var circle = 0; //节流阀变量 var flag=true; //下一页 next.addEventListener('click', function () { //最后一张进行判断 ul复原 left为0 if (num == (ul.children.length - 1)) { ul.style.left = 0; num = 0; } num++; animate(ul, -num * tbpromWidth); circle++; if (circle == 3) { circle = 0; } for (var i = 0; i < ol.children.length; i++) { ol.children[i].className = ''; } ol.children[circle].className = 'one'; }) //上一页 prev.addEventListener('click', function () { if (num == 0) { num = ul.children.length-1; ul.style.left = -num*tbpromWidth+'px'; } else { num--; animate(ul, -num * tbpromWidth); circle--; if (circle <0) { circle = 2; } for (var i = 0; i < ol.children.length; i++) { ol.children[i].className = ''; } ol.children[circle].className = 'one'; } }) //自动播放 var timer=setInterval(function () { next.click();//手动调动点击事件 },2000) </script> </body> </html>
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