向下滑动按钮动画效果 css3动画

 

.up{position:absolute;left:0;right:0;bottom:10px;width:56px;height:62px;margin:auto;display:none;z-index:1000}
.ups{width:56px;height:62px;background:url(../images/up.png) no-repeat;background-size:100%;z-index:100;
　　　animation:up 1s ease-in infinite;-moz-animation:up 1s ease-in infinite;
　　　-webkit-animation:up 1s ease-in infinite;
position:absolute;left:0;bottom:10px}
@keyframes up{
    0%{transform:translateY(0);opacity:0}
    50%{transform:translateY(-20px);opacity:1}
    100%{transform:translateY(-40px);opacity:0}
}
@-webkit-keyframes up{
    0%{-webkit-transform:translateY(0);opacity:0}
    50%{-webkit-transform:translateY(-20px);opacity:1}
    100%{-webkit-transform:translateY(-40px);opacity:0}
}