计算内容区向下滚动高度

<template>
    <div id="from-top" class="content">
    </div>
</template>

<script>
export default {
    data(){
        return{
      }
    },
    mounted(){
        this.mainContent = document.getElementById("from-top");
        this.mainContent.addEventListener("scroll", this.getElementScrollTop);
    },
    methods: {
        getElementScrollTop(e) {
            this.scrollTop = document.getElementById("from-top").scrollTop;
            console.log(this.scrollTop);
        },
    },
}
</script>