Vue实现监听窗口关闭事件,并在窗口关闭前发送请求

mounted() {
   window.addEventListener('beforeunload', e => this.beforeunloadHandler(e))
   window.addEventListener('unload', e => this.unloadHandler(e))
  },
  destroyed() {
   window.removeEventListener('beforeunload', e => this.beforeunloadHandler(e))
   window.removeEventListener('unload', e => this.unloadHandler(e))
  },
  methods: {
   beforeunloadHandler(){
    this._beforeUnload_time=new Date().getTime();
   },
   unloadHandler(e){
    this._gap_time=new Date().getTime()-this._beforeUnload_time;
    debugger
    //判断是窗口关闭还是刷新
    if(this._gap_time<=5){
     //如果是登录状态，关闭窗口前，移除用户
     if(!this.showLoginButton){
      $.ajax({
       url: '/pictureweb/user/remove',
       type: 'get',
       async:false, //或false,是否异步
       
      })
     }
    }
   },
}

window.Onbeforeunload= function (e) {
 e = e || window.event;
 // 兼容IE8和Firefox 4之前的版本
 if (e) {
  e.returnValue = '关闭提示';
 }
 // Chrome, Safari, Firefox 4+, Opera 12+ , IE 9+
 return '关闭提示';
}; 

let _this = this
  window.Onbeforeunload= function (e) {
   if (_this.$route.name == "dyyPerformanceCenterSale") {
    e = e || window.event;
    // 兼容IE8和Firefox 4之前的版本
    if (e) {
     e.returnValue = '关闭提示1111';
    }
    // Chrome, Safari, Firefox 4+, Opera 12+ , IE 9+
    return '关闭提示222';
   } else {
    window.Onbeforeunload= null
   }
  };