<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
.father {
width: 300px;
height: 300px;
background-color: pink;
margin: 100px auto;
}
.son {
width: 200px;
height: 200px;
background-color: purple;
}
</style>
</head>
<body>
<div class="father">
<div class="son"></div>
</div>
<script>
var father = document.querySelector('.father');
var son = document.querySelector('.son');
father.addEventListener('mouseenter', function() {
console.log(11);
})
</script>
</body>
</html>
