IE8透明度问题

filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#7f0591d9,endColorstr=#7f0591d9);
0.1-19 0.2-33 0.3-4c 0.4-66 0.5-7f 0.6-99 0.7-b2 0.8-c8 0.9-e5

filter: alpha(opacity=50);

filter: progid:DXImageTransform.Microsoft.Alpha(opacity=70)