为什么在javascript对象中设置属性不起作用？

Question

 class GotoMeeting {
  constructor() {
    //get the dom element
    let self = this;
    this.audioBtn = null;
    this.email = null;
    this.name = null;
    self.clicked = false;
  }
  getElement() {
    let target = document.body;
    let MutationObserver =
      window.MutationObserver ||
      window.WebKitMutationObserver ||
      window.MozMutationObserver;
    let mutation = new MutationObserver(mutations => {
      mutations.forEach(function(mutation) {
        console.log(mutation.type);
      });
      this.audioBtn = document.getElementById("select-audio-none");
      let emailBtn = document.getElementById("join-email");
      let nameBtn = document.getElementById("join-name");
      let submitBtn = document.getElementById("join-submit");
      if (this.audioBtn) {
        this.audioBtn.click();
      }

      if (emailBtn && nameBtn) {
            if (this.email !== null && this.name !== null) {
                emailBtn.value = this.email;
                nameBtn.value = this.name;
                if (self.clicked === false && emailBtn.value && nameBtn.value) {
                  submitBtn.click();
                  self.clicked === true;
                  console.log("it worked :)")
                }
              }else{
                  setTimeout(()=>{checkDetail()},1000);
              }
        this.triggerMouseEvent(nameBtn, "keydown");
      }
    });
    let config = {
      childList: true,
      subtree: true
    };
    mutation.observe(target, config);
  }
  triggerMouseEvent(node, eventType) {
    let keyboardEvent = new KeyboardEvent(eventType);
    node.dispatchEvent(keyboardEvent);
  }
}
 let gotomeeting = new GotoMeeting();
  gotomeeting.getElement();

iam调用getElement()方法的原因是因为它必须在页面加载时加载，因为它有变异观察者。

我从另一个网站上获取了一些电子邮件和名字，我也得到了   响应，但在确定此对象的值gotomeeting时不起作用 并且检查电子邮件的if语句没有执行    gotomeeting.email = (response from other site) 任何人都可以告诉我为什么回应没有将价值赋予

gotomeeting object property email and name