vue监听滚动事件

        mounted() {
            this.$nextTick(() => {
            // 添加滚动事件
                window.addEventListener('scroll', this.scrollWindow)
            })
        },
        methods() {
			scrollWindow() {
				var scrollTop = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop;
			},
			destroyed() {
			// 离开取消监听滚动事件
                window.removeEventListener('scroll', this.scrollWindow)
            },
		},
		beforeDestroy() {
            this.destroyed()
        },