CSS3动画箭头

<style type="text/css">

.arrow {
    display: block;
    width: 20px;
    height: 20px;
    position: absolute;
    bottom: 25px;
    left: 50%;
    margin-left: -11px;
    border: 3px solid transparent;
    border-top: 3px solid #000;
    border-left: 3px solid #000;
    z-index: 99;
    opacity: .8;
    -webkit-transform: rotate(45deg);
    -webkit-animation: arrow 1.5s infinite ease-in-out;
}
 
@-webkit-keyframes arrow {
0% {
opacity:0;
-webkit-transform:translate(0, 0px) rotate(45deg)
}
50% {
opacity:1;
-webkit-transform:translate(0, -5px) rotate(45deg)
}
100% {
opacity:0;
-webkit-transform:translate(0, -10px) rotate(45deg)
}
}

</style>



<div class="arrow"></div>