border-radius

css2 border-radius：用图片

css3 border-radius: firefox3.5+ safari3.0+ chrome 4.0+ opera 10.5+ ie 9+

w3c: border-radius:  <length>{1}：4角相等， <length>{2}交叉相等， <length>{3}右上左下相等 , <length>{1,4} / <length> {1,4} 前面水平半径，后面垂直半径

        border-top-left-radius/border-top-right-radius/border-bottom-left-radius/border-bottom-right-radius: <length>  <length>

        firefox4 safari5 chrome 10 opera 10.5 ie9

  -moz-border-radius-topleft: <length> <length> //左上角
  -moz-border-radius-topright: <length> <length> //右上角
  -moz-border-radius-bottomright: <length> <length> //右下角
  -moz-border-radius-bottomleft: <length> <length> //左下角
  -webkit-border-top-left-radius:  <length> <length> //左上角
  -webkit-border-top-right-radius:  <length> <length> //右上角
  -webkit-border-bottom-right-radius: <length> <length> //右下角
  -webkit-border-bottom-left-radius:  <length> <length> // 左下角
  border-top-left-radius: <length> <length> //左上角
  border-top-right-radius: <length> <length> //右上角
  border-bottom-right-radius: <length> <length> //右下角
  border-bottom-left-radius: <length> <length> //左下角