// 滚动到底部
            handleScrollBottom(){
                this.$nextTick(function () {
                    // 设置滚动最底部
                    let msgBody = document.getElementsByClassName('message-body')[0]
                    //设置滚动条到最底部
                    if(msgBody.scrollHeight > msgBody.clientHeight) {
                        setTimeout(function () {
                            //设置滚动条到最底部
                            msgBody.scrollTop = msgBody.scrollHeight;
                        }, 0);
                    }
                })
            },
            // 滚动到顶部加载上一页
            handlerScrollTop () {
                let _this = this
                let msgBody = document.getElementsByClassName('message-body')[0]
                if (_this.topStatus === 'more' && msgBody.scrollTop <= 100) {
                    // console.log('执行触顶加载', msgBody.scrollHeight, msgBody.scrollTop)
                    _this.nextMessageList()
                }
            },

使用方法

// 滚动到底部
                    _this.handleScrollBottom()

                    // 监听滚动到顶部
                    _this.$nextTick(function () {
                        let msgBody = document.getElementsByClassName('message-body')[0]
                        msgBody.addEventListener('scroll', _this.handlerScrollTop)
                    })