transition 过渡动画
div
{
transition: width 2s;
-moz-transition: width 2s; /* Firefox 4 */
-webkit-transition: width 2s; /* Safari 和 Chrome */
-o-transition: width 2s; /* Opera */
}
div
{
transition: width 2s;
-moz-transition: width 2s; /* Firefox 4 */
-webkit-transition: width 2s; /* Safari 和 Chrome */
-o-transition: width 2s; /* Opera */
}