1.在入口文件index.html中加入loading动画：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="renderer" content="webkit|ie-comp|ie-stand">
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport">
<!--浏览器兼容模式用最新的文档渲染模式-->
<meta http-equiv="X-UA-Compatible" content ="IE=edge"/>
<title></title>
<style type="text/css">
#Loading {
top:50%;
left:50%;
position: absolute;
-webkit-transform: translateY(-50%) translateX(-50%);
transform: translateY(-50%) translateX(-50%);
z-index:100;
}
@-webkit-keyframes ball-beat {
50% {
opacity: 0.2;
-webkit-transform: scale(0.75);
transform: scale(0.75); }
100% {
opacity: 1;
-webkit-transform: scale(1);
transform: scale(1); } }
@keyframes ball-beat {
50% {
opacity: 0.2;
-webkit-transform: scale(0.75);
transform: scale(0.75); }
100% {
opacity: 1;
-webkit-transform: scale(1);
transform: scale(1); } }
.ball-beat > div {
background-color: #279fcf;
width: 15px;
height: 15px;
border-radius: 100% !important;
margin: 2px;
-webkit-animation-fill-mode: both;
animation-fill-mode: both;
display: inline-block;
-webkit-animation: ball-beat 0.7s 0s infinite linear;
animation: ball-beat 0.7s 0s infinite linear; }
.ball-beat > div:nth-child(2n-1) {
-webkit-animation-delay: 0.35s !important;
animation-delay: 0.35s !important; }
</style>
</head>
<body>
<div id="Loading">
<div class="loader-inner ball-beat">
<div></div>
<div></div>
<div></div>
</div>
</div>
<div id="app"></div>
<!-- built files will be auto injected -->
</body>
</html>
2.在app.vue的created方法中：
created() { document.body.removeChild(document.getElementById('Loading'))
}效果如下： 
