this绑定相关面试题

function foo() {
  console.log(this);
}

var obj1 = {
  name: "obj1",
  foo: foo,
};

var obj2 = {
  name: "obj2",
}

(obj2.foo = obj1.foo)();

var name = "全局window";

var person = {
  name: "person",
  sayName: function () {
    console.log(this.name);
  }
}
function sayName() {
  var fun = person.sayName;
  fun();// 全局window
  person.sayName(); //person
  (b = person.sayName)();// 全局window对象
}
sayName();