var a;
  a = 10;
  a = "Dart";
  print(a);

  dynamic b = 20;
  b = "JavaScript";
  print(b);
  print(b.runtimeType);

  var list = new List<dynamic>();
  list.add(1);
  list.add("hello");
  list.add(true);
  print(list);


  print("\n");
  dynamic x ='hal';
  print(x.runtimeType);//数据类型
  print(x);

  x = 123;
  print(x.runtimeType);
  print(x);

  var a1 = 'var';
  print(a1.runtimeType);
  print(a1);

  // Object
  Object o1 ='111';
  print(o1.runtimeType);
  print(o1);
  o1.toString();
  print(o1);

Dart
JavaScript
String
[1, hello, true]


String
hal
int
123
String
var
String
111
111