纯css loadigin

<div class="a_load"></div>

  .a_load{
        position: relative;
        bottom: 20px;
        border-radius: 50%;
        margin: 0 auto;
        background: #fff;
        width: 20px;
        height: 20px;
        border-top:4px solid #387cff;    //颜色看个人喜好
        border-left: 4px solid #387cff;
        border-right: 4px solid #387cff;
        border-bottom: 4px solid #f0f0f0;  
        animation: loading 2s infinite;
    }
    @keyframes loading{
        0%{
            transform: rotate(0deg);
        }
        100%{
            transform: rotate(360deg);
        }
    }