运行效果：
代码如下：
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>随机点名</title>
</head>
<style>
body{
background-image: url(img/bg.png);
}
.big{
background-color: aliceblue;
width:400px;
height: 500px;
border-radius: 30px;
margin: 50px auto;
padding-top: 20px;
}
.title{
font-size: 50px;
text-align: center;
font-weight: 520;
}
#show {
width: 300px;
height: 200px;
background-color: aliceblue;
line-height: 200px;
font-size: 30px;
text-align: center;
border: 1.5px solid black;
border-radius: 10px;
margin: 20px auto;
}
.button{
margin: 10px 85px;
}
.start{
height: 40px;
margin: auto;
width: 100px;
}
.end{
margin-left:20px;
height: 40px;
width: 100px;
}
#div1 {
width: 350px;
height: 50px;
background-color: aliceblue;
line-height: 50px;
text-align: center;
font-size: 30px;
border: 1px solid black;
margin: 20px auto;
}
.footer{
text-align: right;
}
</style>
<body>
<div class="big" >
<div class="title">随机点名</div>
<div id="show"></div>
<div class="button">
<button class="start" onclick="startName()" >开始点名</button>
<button class="end" onclick="endName()" >结束点名</button>
</div>
<div id="div1"></div>
</div>
</body>
<script>
var names = ['张三', '李四', '王五',
'张杰', '谢娜', '何炅',
'李维嘉', '吴昕', '杜海涛',
'沈梦辰', '王一博', '肖杰'];
var interval;
var div1 = document.querySelector('#div1');
var show = document.querySelector('#show');
var number;
show.innerHTML="亲,准备后点名了吗?";
function startName() {
clearInterval(interval);
interval = setInterval(function () {
number = Math.random() * (names.length - 1);
number = Math.round(number);
show.innerHTML = names[number];
}, 50);
};
function endName() {
clearInterval(interval);
div1.innerHTML = "请"+names[number]+"同学回答问题";
};
</script>
<footer class="footer">
king
</footer>
</html>