<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
*{
padding: 0;
margin: 0;
}
.kg{
45px;
height: 20px;
background-color: #dcdfe6;
border-radius: 10px;
border: 2px solid #dcdfe6;
}
.kg::after{
transition: left 0.5s;
display: block;
left: 1px;
top:2px;
position: absolute;
content: "";
20px;
height: 20px;
border-radius: 10px;
background-color: #fff;
}
.hh{
border-color: #409eff;
background-color: #409eff;
}
.hh::after{
left: 28px;
}
</style>
</head>
<body>
<div class="kg">
</div>
<script>
var kg=document.querySelector(".kg");
kg.onclick=function () {
this.classList.toggle("hh")
}
</script>
</body>
</html>