1. prompt()
Refer to https://www.w3school.com.cn/jsref/met_win_prompt.asp
<html>
<head>
<script type="text/javascript">
function display(){
var name = prompt("Please enter your name",'origin')
if(name != null && name != "") {
document.write("hello " + name)
}
}
</script>
</head>
<body>
<input type="button" onclick="display()" value="Display box">
</body>
</html>
2. classList
Refer to https://www.runoob.com/jsref/prop-element-classlist.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
<style>
.mystyle {
300px;
height: 50px;
background-color: coral;
color: white;
font-size: 25px;
}
</style>
</head>
<body>
<p>点击按钮为 DIV 元素添加 "mystyle" 类。</p>
<button onclick="myFunction()">点我</button>
<p><strong>注意：</strong> Internet Explorer 9 及更早 IE 版本浏览器不支持 classList 属性。</p>
<div id="myDIV">
我是一个 DIV 元素。
</div>
<script>
function myFunction() {
document.getElementById("myDIV").classList.add("mystyle");
}
</script>
</body>
</html>