flex兼容性写法

display: -webkit-box;/* OLD - iOS 6-, Safari 3.1-6 */

display: -moz-box;/* OLD - Firefox 19- (buggy but mostly works) */

display: -ms-flexbox;/* TWEENER - IE 10 */

display: -webkit-flex;/* NEW - Chrome */

display: flex;/* NEW, Spec - Opera 12.1, Firefox 20+ */

 -webkit-box-flex:1;/* OLD - iOS 6-, Safari 3.1-6 */

-moz-box-flex:1;/* OLD - Firefox 19- */

width:20%;/* For old syntax, otherwise collapses. */

-webkit-flex:1;/* Chrome */

-ms-flex:1;/* IE 10 */

flex:1;/* NEW, Spec - Opera 12.1, Firefox 20+ */