CSS3之渐变色按钮

.my_btn
{
background: linear-gradient(bottom,blue,#fff);
background: -ms-linear-gradient(bottom,blue,#fff);
background: -webkit-linear-gradient(bottom,blue,#fff);
background: -o-linear-gradient(bottom,blue,#fff);
background: -moz-linear-gradient(bottom,blue,#fff);

width:80%;
height:2em;
border-radius:25px;
text-align: center;
vertical-align: middle;
margin-left: 10%;
font-size:1.6em;
z-index: 999;
}