anchor.diff:    var index = classesselector.selectedIndex;
     teacherselector.options[index].selected = true;
     chooseclassCourse = classesselector.options[index].firstChild.nodeValue;  //这条语句可以获取到option的值，获取到两个option的值之后传到服务器写入/调出课程评价
  -  //querySelector('#Myclassbt').text = chooseclassCourse;
  +  var path = 'http://127.0.0.1:8008/showmes';
  +  var httpRequest = new HttpRequest();
  +  httpRequest
  +    ..open('POST', path)
  +    ..send(JSON.encode(chooseclassCourse))
  +    ..onLoadEnd.listen((e) => requestMesComplete(httpRequest));
   }
   
   void ChangeClassname(Event e){
     var index = teacherselector.selectedIndex;
     classesselector.options[index].selected = true;
     chooseclassTeacher = classesselector.options[index].firstChild.nodeValue;
  +  chooseclassCourse = classesselector.options[index].firstChild.nodeValue;
  +  var path = 'http://127.0.0.1:8008/showmes';
  +  var httpRequest = new HttpRequest();
  +  httpRequest
  +    ..open('POST', path)
  +    ..send(JSON.encode(chooseclassCourse))
  +    ..onLoadEnd.listen((e) => requestMesComplete(httpRequest));
   }
   
   void Modeshift(MouseEvent event){               ///转换到标签模式
  
positive.code:     ..clear()
      ..add('Tagtag1');
    querySelector('#Tagtag').onClick.listen(Modeshift);
  }
  
  void Loadsaymywords(){
  
negative.code:     ..clear()
      ..add('Tagtag');
    querySelector('#Tagtime').onClick.listen(Modeshift1);
    var path = 'http://127.0.0.1:8008/showmes';
    var httpRequest = new HttpRequest();
    httpRequest
      ..open('POST', path)
      ..send(JSON.encode(chooseclassCourse))
      ..onLoadEnd.listen((e) => requestMesComplete(httpRequest));
  }
  
  void Modeshift1(MouseEvent event){              ///转换到时间轴
  