css中position:relative和overflow:hidden的问题

<div style="height:100px; width:100px; background:#CCC; overflow:hidden;">
    <div style="height:300px; width:90px; background:#999; position:relative;"></div>
</div>
↓

解决方案：将父标签的position也设置成relative，代码如下：

<div style="height:100px; width:100px; background:#CCC; overflow:hidden; position:relative;">
    <div style="height:300px; width:90px; background:#999; position:relative;"></div>
</div>