background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #ee432e), color-stop(50%, #c63929), color-stop(50%, #b51700), color-stop(100%, #891100));
这个是中间有明显过渡痕迹的,如果需要逐渐过渡的
用
background-image: -webkit-gradient(linear, 0 0, 0 bottom, from(white), to(#D7D7D9));
详情可参考http://hellohappy.org/css3-buttons/
http://www.cnblogs.com/lhb25/p/css3-animated-button-tutorials.html