Uncaught TypeError: Cannot read property 'offsetTop' of undefined at VueComponent.handleScroll

	    mounted() {
			    window.addEventListener("scroll", this.handleScroll);
	    },
	    beforeDestroy() {
                    window.removeEventListener("scroll",this.handleScroll)
            },
        handleScroll() {
	    var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
	    offsetTop = this.$refs.searchBar.offsetTop;
	    problemTop = this.$refs.problem.offsetTop;
	    claimsTop =  this.$refs.claims.offsetTop;
	    if(scrollTop > offsetTop) {
			this.searchBarFixed = true;
	    } else {
			this.searchBarFixed = false;
	   }
	   if(scrollTop >= problemTop && scrollTop < claimsTop) {
			this.current = 1;
	   } else if(scrollTop >= claimsTop) {
			this.current = 2;
	   } else {
			this.current = 0;
	   }
	},

說明

報offsetTop這個錯誤，是因為我在頁面加載的時候給window添加了scroll事件，但是一定要記得銷毀，要不然所有的頁面都會添加這個scroll事件，在這個頁面銷毀前移除這個事件就解決了