The effect of 'position:relative' on table-row-group, table-header-group, table-footer-group, table-row, table-column-group, table-column, table-cell, and table-caption elements is undefined.
解决办法：在外面套个DIV
关于td不支持position问题
今天遇到个问题，就是在FIREFOX里面，td不支持position:relative，百度了下