九宫格随机抽奖功能实现：在选择的时候方格的轮转速度先慢后快再慢的效果
代码如下：
<div class="container"><div class="block1 block">小米笔记本</div><div class="block2 block">iPhoneX</div><div class="block3 block">PS4游戏机</div><div class="block4 block">谢谢参与</div><div class="block5 block">开始抽奖</div><div class="block6 block">索尼电视机</div><div class="block7 block">西门子冰箱</div><div class="block8 block">老板抽油烟机</div><div class="block9 block">空气净化机</div></div>
<style>.container {width: 600px;height: 600px;border: 1px solid;display: flex;flex-wrap: wrap;margin: 100px auto;}.block {width: 33.33%;height: 33.33%;outline: 1px solid black;text-align: center;line-height: 200px;font-size: 26px;}.block5 {background-color: skyblue;cursor: pointer;}</style>
<script>let blocks = document.getElementsByClassName("block");// 数组存放的是盒子的下标，按照顺时针的顺序let arr = [0, 1, 2, 5, 8, 7, 6, 3], i = 0, count = 0, stopTimer;let rand = Math.floor(Math.random() * 8 + 50); // 给出一个停止计时器的随机数 count的值等于这个随机数时停止计时器let around = function () {// 将其他盒子都变为白色for (let j = 0; j < arr.length; j++) {blocks[arr[j]].style.background = "white";}// 这里blocks的取值为 blocks[0] blocks[1] blocks[2] blocks[5] blocks[8] blocks[7] blocks[6] blocks[3]// 将当前arr[i]值所对应的盒子修改为粉色blocks[arr[i]].style.background = "pink";i++; // 重制i的值if (i === arr.length) {i = 0;}count++; // count是一个计数器 根据count的值来调整速度// 下面的4个if根据count的值来关闭计时器和重启计时器 改变计时器的时间间隔if (count === 5 || count === 45) {clearInterval(stopTimer);stopTimer = setInterval(around, 200);}if (count === 10 || count === 35) {clearInterval(stopTimer);stopTimer = setInterval(around, 100);}if (count === 15) {clearInterval(stopTimer);stopTimer = setInterval(around, 50);}// 当等于上面的随机数时，停止计时器if (count === rand) {clearInterval(stopTimer);}}// 给开始按钮绑定点击事件 点击后执行 around let start = function () {blocks[4].removeEventListener("click", start); // 当用户点击了开始按钮后 必须要移除该事件 防止用户重复点击stopTimer = setInterval(around, 300);}blocks[4].addEventListener("click", start);</script>
实现图：
