console
$(function () {
$('.d1').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 xy = Math.round( ( ( (Math.atan2(y, x) * (180 / Math.PI)) + 180) / 90) + 3) % 4;
var eventType = e.type;
var oName = ['上方', '右侧', '下方', '左侧'];
if(e.type == 'mouseenter') {
$(this).text(oName[xy] + '进入');
} else {
$(this).text(oName[xy] + '离开');
}
});
});
<div class="d1">鼠标进入前</div>
.d1 {
width: 400px;
height: 400px;
background: #555;
color: #fff;
margin: 200px auto;
font: 30px/400px Microsoft YaHei;
text-align: center;
}