20170503
1.手机uc不支持伪元素使用animation动画
(暂未解决)
2.移动端background-attachment:fixed不兼容性,没有任何效果,
element:before {
content: ' ';
position: fixed;
z-index: -1;
top: 0;
right: 0;
bottom: 0;
left: 0;
background:#444 url(../img/banner1.jpg) center center no-repeat;
background-size: cover;
overflow: hidden;
}