寫好的函數,判斷移入移出時鼠標從哪個方向進去出來的
// 返回值
// top 0 right 1 bottom 2 left 3
// event 鼠標對象 ele 元素
function getDer(wrap, event) {
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
}