1将animate和过度动画的类名添加到transition对应的类上
2appear 设置初始样式（页面刷新样式）appear-active-class
3type设置动画时间依据类型（transition或animate）
4可以通过:duration来设置动画时间，补充3
<style>
.fade-enter,.fade-leave-to{
opacity: 0;
}
.fade-enter-active,.fade-leave-active{
transition: opacity 1s;
}
</style>
</head>
<body>
<!--
过程如下：
显示 fade-enter,fade-enter-active fade-enter-active,fade-enter-to 空
隐藏 fade-leave,fade-leave-active fade-leave-active,fade-leave-to 空
-->
<div id="root">
<transition name='fade'
appear
appear-active-class='animated tada'
enter-active-class='animated tada fade-enter-active'
leave-active-class='animated rubberBand fade-leave-active'
>
<h1 v-show='show'>
最是年少时模样
</h1>
</transition>
<button @click='change'>切换</button>
</div>
<script>
var vm=new Vue({
el:'#root',
data:{
show:true
},
methods:{
change:function(){
this.show=!this.show;
}
}
})
</script>
</body>