1. 判断鼠标进入 div 的方向
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style>
.demo {
width: 400px;
height: 300px;
background-color: pink;
margin: 100px auto;
}
</style>
<script src="js/jquery-1.11.3.min.js"></script>
<script type="text/javascript">
$(function () {
$('div').on('mouseenter mouseleave', function (e) {
var w = $(this).width();
var h = $(this).height();
var x = (e.pageX - this.offsetLeft - (w / 2)) * (w > h ? (h / w) : 1);
var y = (e.pageY - this.offsetTop - (h / 2)) * (h > w ? (w / h) : 1);
var direction = Math.round((((Math.atan2(y, x) * (180 / Math.PI)) + 180) / 90) + 3) % 4;
var dirName = new Array('上方', '右侧', '下方', '左侧');
if (e.type == 'mouseenter') {
$(this).html(dirName[direction] + '进入');
} else {
$(this).html(dirName[direction] + '离开');
}
});
})
</script>
</head>
<body>
<div class="demo"></div>
</body>
</html>