css设置input框没有边框，选中时取消背景色

 1     input {
 2         outline:none;
 3         background:transparent;
 4         border:none;
 5         outline:medium;
 6     }
 7     *:focus { 
 8         outline: none;
 9         background-color: transparent;
10     }
11     ::selection{background:transparent; }
12     ::-moz-selection{background:transparent; }