css3加载中loading效果代码

html如何利用css3做一个loading动态过渡效果，下面编程教程网小编给大家简单介绍一下实现代码！

html代码：

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

css动态效果代码：

body{
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  background: #69a7f7;
}
.loading,
.loading:before,
.loading:after {
  background: #FFF;
  -webkit-animation: dynamic 1s infinite ease-in-out;
  animation: dynamic 1s infinite ease-in-out;
  width: 1em;
  height: 4em;
}
.loading:before,
.loading:after {
  position: absolute;
  top: 0;
  content: '';
}
.loading:before {
  left: -1.5em;
  -webkit-animation-delay: -0.32s;
  animation-delay: -0.32s;
}
.loading {
  text-indent: -9999em;
  margin: 8em auto;
  position: relative;
  font-size: 11px;
  -webkit-animation-delay: -0.16s;
  animation-delay: -0.16s;
}
.loading:after {
  left: 1.5em;
}
@-webkit-keyframes dynamic {
  0%,
  80%,
  100% {
    box-shadow: 0 0 #FFF;
    height: 4em;
  }
  40% {
    box-shadow: 0 -2em #ffffff;
    height: 5em;
  }
}
@keyframes dynamic {
  0%,
  80%,
  100% {
    box-shadow: 0 0 #FFF;
    height: 4em;
  }
  40% {
    box-shadow: 0 -2em #ffffff;
    height: 5em;
  }
}