var xiaoming = {
name: '小明',
birth: 1990,
school: 'No.1 Middle School',
height: 1.70,
weight: 65,
score: null
};
console.log(name in xiaoming);
console.log(birth in xiaoming); 同样都是用变量检查key是否属于对象,为什么name为false ,birth报错提示undefined!
name: '小明',
birth: 1990,
school: 'No.1 Middle School',
height: 1.70,
weight: 65,
score: null
};
console.log(name in xiaoming);
console.log(birth in xiaoming); 同样都是用变量检查key是否属于对象,为什么name为false ,birth报错提示undefined!
报错是因为birth不存在
你应该改成
console.log('name' in xiaoming);
console.log('birth' in xiaoming);