<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
#box1 {
width: 300px;
height: 300px;
background-color: red;
}
#box2 {
width: 150px;
height: 150px;
background-color: blue;
}
</style>
</head>
<body>
<div id="box1">
<div id="box2">
</div>
</div>
<script>
// mouseenter 和 mouseover的区别
var box1 = document.getElementById('box1');
var i = 0;
// 触发子元素的mouseover，会冒泡到父元素上
// box1.onmouseover = function () {
// i++;
// console.log(i);
// }
//
// 此事件不触发事件冒泡
box1.onmouseenter = function () {
i++;
console.log(i);
}
</script>
</body>
</html>
