CSS实现loading加载效果

body部分代码：

<div class="loading">
        <span></span>
        <span></span>
        <span></span>
        <span></span>
        <span></span>
        <span></span>
        <span></span>
        <span></span>
    </div>

CSS部分代码：

.loading{
            width: 50px;
            height: 50px;
            position: relative;
            margin: 0 auto;
            margin-top:100px;
        }
        .loading span{
            display: inline-block;
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: #ddd;
            position: absolute;
            -webkit-animation: load 1.04s ease infinite;
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
            }
            100%{
                opacity: 0.2;
            }
        }
        .loading span:nth-child(1){
            left: 0;
            top: 50%;
            margin-top:-4px;
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(2){
            left: 7px;
            top: 7px;
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(3){
            left: 50%;
            top: 0;
            margin-left: -4px;
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(4){
            top: 7px;
            right:7px;
            -webkit-animation-delay:0.52s;
        }
        .loading span:nth-child(5){
            right: 0;
            top: 50%;
            margin-top:-4px;
            -webkit-animation-delay:0.65s;
        }
        .loading span:nth-child(6){
            right: 7px;
            bottom:7px;
            -webkit-animation-delay:0.78s;
        }
        .loading span:nth-child(7){
            bottom: 0;
            left: 50%;
            margin-left: -4px;
            -webkit-animation-delay:0.91s;
        }
        .loading span:nth-child(8){
            bottom: 7px;
            left: 7px;
            -webkit-animation-delay:1.04s;
        }

这样就可得到如图的效果