自身属性和原型属性
想问两个结果输出的为什么不一样。
function foo(){}
foo.prototype.z = 5;
var obj = new foo();
obj.z = 7;
console.log(obj.z); //输出7
delete obj.z;
console.log(obj.z);//输出5function foo(){
this.z = 5;
}
var obj = new foo();
obj.z = 7;
console.log(obj.z); //输出7
delete obj.z;
console.log(obj.z);//输出undefined
