JavaScript实现精简版随机点名器

代码实现

<head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>随机点名生成</title>

 <style>
  /* 页面css样式 */
  .wrapper {
   width: 800px;
   margin: 100px auto;
   border: 1px solid #ddd;
   text-align: center;
  }

  .box li {
   vertical-align: top;
   display: inline-block;
   width: 100px;
   height: 50px;
   border: 2px solid #ddd;
   border-radius: 15px;
   text-align: center;
   line-height: 50px;
   margin: 5px;
  }
  
  .wrapper button {
   border: none;
   width: 100px;
   height: 50px;
   border-radius: 10px;
   cursor: pointer;
   outline: none;
   margin-top: 20px;
   font-weight: bolder;
   color: #333;
   background-color: rgb(14, 146, 43);
  }

  .wrapper button {
   display: inline-block;
  }

  body {
   background-color: #eee;
  }
 </style>

</head>

<body>
 <div class="wrapper">
  <h1 align="center">随机点名系统</h2>
  //实时显示系统时间标签
  <h6 id="data" align="right"></h6>
  <ul class="box"></ul>
  <button class="start">开始</button>
  <button class="stop">停止</button>
 </div>
</body>

<script>
 //定义全局变量方便引用
 var boxUl = document.getElementsByClassName('box')[0];
 var start = document.getElementsByClassName('start')[0];
 var stop = document.getElementsByClassName('stop')[0]
 var oLi = document.getElementsByTagName('li');

 //数据准备
 var nameString = new String("张三,李四,王五,赵六,周七,田八,国九,归零,张3,李4,王5,赵6,周7,田8,国9,归0");
 var nameArr = nameString.split(",");

 //获取每个学生姓名添加到标签中，自动解析html标签
 var str = "";
 for (let i = 0; i < nameArr.length; i++) {
  str += "<li >" + nameArr[i] + "</li>"
 }
 boxUl.innerHTML = str;

 //添加开始按钮的点击事件
 var timer = null;
 start.onclick = function () {
  // 设置定时器
  timer = setInterval(function () {

   // 根据数组长度范围生成随机数
   var i = Math.floor(Math.random() * nameArr.length);
   // 先通过for循环清空所有style属性
   for (var j = 0; j < oLi.length; j++) {
    oLi[j].removeAttribute("style");
   }
   // 为随机选择的li颜色属性
   oLi[i].style.background = "red";
  }, 150);
 };
 // 点击停止
 stop.onclick = function () {
  // 清空定时器停止点名
  clearInterval(timer);
 }
 //页面初始化时间设置
 window.onload = function () {
  datatime();
 }
 //页面时间动态刷新
 setInterval(datatime, 1000);

 function datatime() {
  let data = new Date();
  let dataString ="现在是北京时间：" + data.toLocaleString();
  document.getElementById("data").innerHTML = dataString;
 }
</script>