Vue实现回到顶部和底部动画效果

<template>
 <div>
 <div class="scroll" :class="{show:isActive}">
 <div id="toTop" @click="toTop(step)"><</div>
 <div id="toBottom" @click="toBottom(step)">></div>
 </div>
 </div>
</template>
<script>
 export default{
 props:{
 step:{ //此数据是控制动画快慢的
 type:Number,
 default:50 
 }
 },
 data(){
 return {
 isActive:false,
 }
 },
 methods:{
 toTop(i){
 //参数i表示间隔的幅度大小，以此来控制速度
 document.documentElement.scrollTop-=i;
 if (document.documentElement.scrollTop>0) {
 var c=setTimeout(()=>this.toTop(i),16);
 }else {
 clearTimeout(c);
 }
 },
 toBottom(i){
 var clientHeight=document.documentElement.clientHeight||document.body.clientHeight;
 var scrollHeight=document.documentElement.scrollHeight;
 var height=scrollHeight-clientHeight; //超出窗口上界的值就是底部的scrolTop的值
 document.documentElement.scrollTop+=i;
 if (document.documentElement.scrollTop<height) {
 var c=setTimeout(()=>this.toBottom(i),16);
 }else {
 clearTimeout(c);
 }
 }
 },
 created(){
 var vm=this;
 window.οnscrοll=function(){
 if (document.documentElement.scrollTop>60) {
 vm.isActive=true;
 }else {
 vm.isActive=false;
 }
 }
 }
 }
</script>
<style scoped>
 .scroll{
 position: fixed;
 right: 10px;
 bottom: 60px;
 width: 45px;
 height: 90px;
 cursor: pointer;
 display: none;
 }
 .scroll>div{
 width: 45px;
 height: 45px;
 transform: rotate(90deg);
 line-height: 45px;
 text-align: center;
 font-size: 35px;
 font-family: "黑体";
 background-color: rgba(0,0,0,.2);
 color: #fff;
 }
 .scroll>div:hover{
 background-color: rgba(0,0,0,.5);
 }
 .show{
 display: block;
 }
</style>