PC端鼠标移入移出的效果很好，这里就给出判断鼠标移入移出的方法，有空再发出带效果的文章，不过授之以鱼不如受之以渔，有了个这个方法，效果不还是so easy吗？
代码：
<!DOCTYPE html>
<html lang="zh">
<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></title>
<style type="text/css">
* {
padding: 0;
margin: 0;
}
.ul-box {
width: 345px;
margin: 20px auto;
background-color: #f5f5f5;
overflow: auto;
}
.li-item {
width: 100%;
height: 134px;
margin-bottom: 10px;
border-radius: 4px;
}
.li-item1 {
background: linear-gradient(90deg, #7f90e3 0%, #8b9bff 100%);
}
</style>
</head>
<body>
<ul id="ulBox" class="ul-box">
<li class="li-item li-item1" onmouseleave="derEvent(event, 'leave')" onmouseenter="derEvent(event, 'enter')"></li>
</ul>
</body>
<script type="text/javascript">
/**
* @param {Object} event 当前事件源信息
* @return {Number} d 方向 top 0 right 1 bottom 2 left 3
*/
function getDer(event) {
let ele = event.target
var d;
var w = ele.offsetWidth,
h = ele.offsetHeight,
l = ele.offsetLeft,
t = ele.offsetTop,
x = (event.clientX - l - w / 2) * (w > h ? (h / w) : 1),
y = (event.clientY - t - h / 2) * (h > w ? (w / h) : 1);
d = (Math.round((Math.atan2(y, x) * (180 / Math.PI) + 180) / 90) + 3) % 4;
return d;
// top 0 right 1 bottom 2 left 3
}
/**
* @param {Object} event 事件源信息
* @param {Object} type 类型 leave 离开 色 enter 进入
*/
function derEvent(event, type) {
let d = getDer(event)
let txt = ''
switch (d) {
case 0:
txt = '上'
break;
case 1:
txt = '右'
break;
case 2:
txt = '下'
break;
case 3:
txt = '左'
break;
default:
break;
}
if (type === 'leave') {
console.log(txt, '离开')
} else {
console.log(txt, '进入')
}
}
</script>
</html>
