js检测两个元素是否产生交集

1、js代码如下：<衡痕贤伎script type="text/javascript">function collision(a, b) { var ax = a.offsetLeft; var ay = a.offsetTop; var aw = a.offsetWidth; var ah = a.offsetHeight; var bx = b.offsetLeft; var by = b.offsetTop; var bw = b.offsetWidth; var bh = b.offsetHeight; return (ax + aw > bx && ax < bx + bw && ay + ah > by && ay < by + bh);}alert(collision($('#a'), $('#b')));</script>

2、html结构代码：<div id="a"></div><div id="b"></div>

3、这种情况两个div没有交集，最后会弹出false。如图：