anchor.diff:  import "dart:html";
   import 'dart:convert';
   import 'package:dnd/dnd.dart';
  +import 'dart:math';
   
   
   class UserElement{
  
positive.code:     LoadMesContain(id,color);
  
      MesContain.onDrag.listen(DragMesContain);
      print("Finish loading");
    }//构造函数
    DragMesContain(Event e){
  
    }
    LoadMesContain(String id,String color){
      MesContain
        ..classes.add("MesDiv")
        ..id = id;
      MesContain.style
        ..backgroundColor=color
        ..width="300px"
        ..height= "200px";
      container.children.add(MesContain);
      Draggable draggable = new Draggable(querySelector('#'+MesContain.id),
      avatarHandler: new AvatarHandler.original());
  
negative.code:     this.zan = zan;
      container = querySelector('#'+containerID);
  
  
      LoadClose();
      LoadLabel();
      LoadZan();
  