+++++++++++++++++
CSS HACK
+++++++++++++++++
IE6.0
能识别 _background:#ff00ff; *background:#ff00ff; +background:#FF00FF;(不确定)
不能识别 backgound:#f00ff !important;优先级的提升
IE7.0
能识别 *background:#ff00ff; backgound:#f00ff !important;优先级的提升 +background:#FF00FF;
不能识别 _background:#ff00ff;
FF
能识别 backgound:#f00ff !important;优先级的提升
不能识别 _background:#ff00ff; *background:#ff00ff; +background:#FF00FF;
故区别FF,IE7，IE6
background:orange;*background:green;_background:blue;
background:orange;*background:green !important;*background:blue;
IE8.0 IE9.0
background-color:red\0;IE8和IE9都支持；background-color:blue\9\0; 仅IE9支持；
background-color:red\9; 所有IE浏览器(ie6+)支持