加载动画，3个小长方形块，一个一个变大，抖动那样子

loading-animate

//css
#loading{
  position: fixed;
  width: 40px;
  height: 20px;
  top: 50%;
  left: 50%;
  margin-left: -20px;
  margin-top: -10px;
}
@-webkit-keyframes uil-facebook {
  0% {
    -webkit-transform: scale(2);
    transform: scale(2);
  }
  90% {
    -webkit-transform: scale(1);
    transform: scale(1);
  }
  100% {
    -webkit-transform: scale(1);
    transform: scale(1);
  }
}
.uil-facebook-css {
  background: none;
  position: relative;
  width: 140px;
  height: 140px;
}
.uil-facebook-css > div {
  position: absolute;
  width: 10px;
  height: 20px;
  top: 0px;
  left: 0px;
  background: #ff6600;
  opacity: 0.6;
  -webkit-animation: uil-facebook 1s cubic-bezier(0.01, 0.73, 0.28, 0.93) infinite;
  animation: uil-facebook 1s cubic-bezier(0.01, 0.73, 0.28, 0.93) infinite;
}
.uil-facebook-css > div:nth-of-type(2) {
  left: 15px;
  opacity: 0.8;
  -webkit-animation-delay: 0.2s;
  animation-delay: 0.2s;
}
.uil-facebook-css > div:nth-of-type(3) {
  left: 30px;
  opacity: 0.9;
  -webkit-animation-delay: 0.4s;
  animation-delay: 0.4s;
}


//html

<div id="loading" class="uil-facebook-css"><div></div><div></div><div></div></div>