JavaScript最简单的轮播图

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <style>
        * {
            margin: 0;
            padding: 0
        }

        ul {
            list-style: none
        }

        img {
            vertical-align: top
        }

        .box {
             730px;
            height: 454px;
            margin: 100px auto;
            padding: 5px;
            border: 1px solid #ccc;
        }

        .inner {
             730px;
            height: 454px;
            background-color: pink;
            overflow: hidden;
            position: relative;
        }

        .inner ul {
             1000%;
            position: absolute;
            top: 0;
            left: 0;
        }

        .inner li {
            float: left;
        }

        .square {
            position: absolute;
            right: 10px;
            bottom: 10px;
        }

        .square span {
            display: inline-block;
             16px;
            height: 16px;
            background-color: #fff;
            text-align: center;
            line-height: 16px;
            cursor: pointer;
        }

        .square span.current {
            background-color: orangered;
            color: #fff;
        }

    </style>
</head>
<body>
<div class="box" id="box">
    <div class="inner"><!--相框-->
        <ul>
            <li><a href="#"><img src="images/1.jpg" alt=""/></a></li>
            <li><a href="#"><img src="images/2.jpg" alt=""/></a></li>
            <li><a href="#"><img src="images/3.jpg" alt=""/></a></li>
            <li><a href="#"><img src="images/4.jpg" alt=""/></a></li>
            <li><a href="#"><img src="images/5.jpg" alt=""/></a></li>
            <li><a href="#"><img src="images/6.jpg" alt=""/></a></li>
        </ul>
        <div class="square">
            <span class="current">1</span>
            <span>2</span>
            <span>3</span>
            <span>4</span>
            <span>5</span>
            <span>6</span>
        </div>
    </div>
</div>
<script src="common.js"></script>
<script>
    //获取最外面的div
    var box = my$("box");
    //获取相框
    var inner = box.children[0];
    //获取相框宽度
    var imgWidth = inner.offsetWidth;
    //获取ul
    var ulObj = inner.children[0];
    //获取所有的span
    var spans = inner.children[1].children;
    //循环遍历所有的span注册鼠标进入事件
    for (var i = 0; i < spans.length; i++) {
        //循环的时候把索引保存到每个span的自定义属性中
        spans[i].setAttribute("index", i);
        //注册鼠标进入事件
        spans[i].onmouseover = function () {
            //去掉所有的span的背景颜色
            for (var j = 0; j < spans.length; j++) {
                //移除了每个span标签的类样式
                spans[j].removeAttribute("class");
            }
            //设置当前的span的背景颜色
            this.className = "current";
            //移动ul(每个图片的宽*鼠标放在这个按钮的索引值)
            //获取当前鼠标进入的span的索引
            var index = this.getAttribute("index");
            animate(ulObj, -index * imgWidth);
        };
    }
    //设置任意的一个元素,移动到指定的目标位置
    function animate(element, target) {
        clearInterval(element.timeId);
        //定时器的id值存储到对象的一个属性中
        element.timeId = setInterval(function () {
            //获取元素的当前的位置,数字类型
            var current = element.offsetLeft;
            //每次移动的距离
            var step = 10;
            step = current < target ? step : -step;
            //当前移动到位置
            current += step;
            if (Math.abs(current - target) > Math.abs(step)) {
                element.style.left = current + "px";
            } else {
                //清理定时器
                clearInterval(element.timeId);
                //直接到达目标
                element.style.left = target + "px";
            }
        }, 5);
    }

</script>
</body>
</html>
效果