<html>
<head>鼠标离开方向检测</head>
<body>
<div id="msg">鼠标放到框上，然后移开。</div>
<div id="wrap" style="width:200px; height: 100px; line-height:30px; margin: 100px auto; text-align: center; border: 1px solid #99bbe8;">↖↑↗<br/>← →<br/>↙↓↘</div>
<script src="http://common.cnblogs.com/script/jquery.js"></script>
<script>
$("#wrap").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) / 45) + 3) % 8;
var dirName = ['右下', '下', '左下', '左', '左上', '上', '右上', '右'];
if(e.type == 'mouseenter'){
$("#msg").html(dirName[direction]+'-进入');
}else{
$('#msg').html(dirName[direction]+'-离开');
}
});
</script>
</body>
</html>
