#grad2 {
height: 440px;
width: 440px;
border-radius: %;
background: -webkit-radial-gradient(closest-corner,rgba(,,,0.9)%,rgba(,,,0.8)%,rgba(,,,0.6)%,rgba(,,,0.4)%,rgba(,,,0.2)%); /* Safari 5.1 - 6.0 */
background: -o-radial-gradient(closest-corner,rgba(,,,0.9)%,rgba(,,,0.8)%,rgba(,,,0.6)%,rgba(,,,0.4)%,rgba(,,,0.2)%); /* Opera 11.6 - 12.0 */
background: -moz-radial-gradient(closest-corner,rgba(,,,0.9)%,rgba(,,,0.8)%,rgba(,,,0.6)%,rgba(,,,0.4)%,rgba(,,,0.2)%); /* Firefox 3.6 - 15 */
background: radial-gradient(closest-corner,rgba(,,,0.9)%,rgba(,,,0.8)%,rgba(,,,0.6)%,rgba(,,,0.4)%,rgba(,,,0.2)%); /* 标准的语法（必须放在最后） */
/* Firefox 3.6+ */
background: -moz-radial-gradient(circle, #ace, #f96);
/* Safari 4-5, Chrome 1-9 */
/* Can't specify a percentage size? Laaaaaame. */
background: -webkit-gradient(radial, center center, , center center, , from(#ace), to(#f96));
/* Safari 5.1+, Chrome 10+ */
background: -webkit-radial-gradient(circle, #ace, #f96);
}做了尝试后，失败了。