css透明度的问题，做一下备注：

  1. .transparent_class {  

  2.     background: rgba(255, 0, 0, 0.3) !important; /* IE无效，FF有效 */    

  3.     filter: alpha(opacity=80);    

  4.     -moz-opacity:0.8;    

  5.     -khtml-opacity: 0.3;    

  6.     opacity: 0.8;    

  7. }