一、div在body里垂直水平居中

  1. body {
  2.   background: black;
  4.   margin: 0;
  5.   position: relative;
  6. }
  8. div[id^="vjs_video_"]{
  9.   position: fixed;
  10.   top: 50%;
  11.   left: 50%;
  12.   -webkit-transform: translate(-50%,-50%);
  13.   -moz-transform: translate(-50%,-50%);
  14.   transform: translate(-50%,-50%);
  15. }
  1. body {
  2.     margin: 0;
  3.     display: inline-block;
  4. }
  6. div {
  7.     postion: absolute;
  8.     top: 50%;
  9.     left: 50%;
  10.     -webkit-transform: translate(-50%,-50%);
  11.     -moz-transform: translate(-50%,-50%);
  12.     transform: translate(-50%,-50%);
  13. }

二、边框为内边框

box-sizing: border-box;