css – Chrome和Safari浏览器中的线性渐变

我无法在Safari和Chrome中显示线性渐变.在Firefox中它显示正常.

我在尝试：

BACkground: -webkit-linear-gradient(center top,#9E9E9E,#454545) repeat scroll 0 0 transparent;   
BACkground:    -moz-linear-gradient(center top,#454545) repeat scroll 0 0 transparent;
BACkground:     -ms-linear-gradient(center top,#454545) repeat scroll 0 0 transparent;
BACkground:      -o-linear-gradient(center top,#454545) repeat scroll 0 0 transparent;

感谢您的帮助.

BACkground-color: #9e9e9e;
  BACkground-image: linear-gradient(to bottom,#9e9e9e,#454545);