js获取抖音弹幕

function dom() {       // 创建一个MutationObserver实例       let mutationObserver = new MutationObserver(function(mutationsList, observer) {           for(var mutation of mutationsList) {               console.log("用户：",mutation.target.lastChild.lastChild.childNodes[1].textContent,'信息：', mutation.target.lastChild.lastChild.lastChild.textContent);           }       });       // 选择要监视的DOM元素，这里假设是抖音Web端的弹幕容器       let targetElement = document.querySelector("#_douyin_live_scroll_container_ > div > div > .Iy_uuM55 > .__playerIsFullChatroom > .ro3xcipQ > .lF9JOwdS > div > .webcast-chatroom___messages > div > .webcast-chatroom___item-offset > div > div:nth-child(1)");         if(targetElement){           // 启动观察器，开始监视目标元素的变化           mutationObserver.observe(targetElement, { attributes: true, childList: true });       }else{           console.log('Target element not found');       }   }