专门针对IE的hack写法:

_background:red;/*IE 6*/

*background:black;/*IE7*/

background:blue\9;/*在IE6,IE7,IE8,IE9,IE10下生效*/

background:green\0;/*在E8,IE9,IE10下生效*/

background:grey\9\0;/*在IE9,IE10下生效*/