<div class="aside-nav" v-if="btnFlag">
			<el-button class="backTop" @click="backTop">
				<i class="el-icon-caret-top"></i>
				<div class="backTop-tt">top</div>
			</el-button>
			<el-button class="kefu" @click="dialogVisible = true">
				<i class="iconfont icon-kefu"></i>
				<div class="kefu-tt">免费咨询</div>
			</el-button>
		</div>

data() {
			return {
				key: '',
				btnFlag:true,
				dialogVisible:false
			};
		},
		components: {
			FormModal
		},
		methods: {
			backTop() {
				var that = this
				let timer = setInterval(() => {
					let ispeed = Math.floor(-that.scrollTop / 5)
					document.documentElement.scrollTop = document.body.scrollTop = that.scrollTop + ispeed
					if (that.scrollTop == 0) {
						clearInterval(timer)
					}
				}, 16)
			},
			scrollToTop() {
				var that = this
				let scrollTop = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop
				that.scrollTop = scrollTop
				if (that.scrollTop > 0) {
					that.btnFlag = true
				} else {
					that.btnFlag = false
				}
			}
		},
		mounted() {
			new this.$wow.WOW().init();
			window.addEventListener('scroll', this.scrollToTop)
		},
		destroyed() {
			window.removeEventListener()('scroll', this.scrollToTop)
		}