javascript函数传参是传值还是传引用？

Question

function changeStuff(num, obj1, obj2){    num = num * 10;    obj1.item = "changed";    obj2 = {item: "changed"};}var num = 10;var obj1 = {item: "unchanged"};var obj2 = {item: "unchanged"};changeStuff(num, obj1, obj2);console.log(num);   // 10console.log(obj1.item);    // changedconsole.log(obj2.item);    // unchanged为什么是这个情况？

Answer 1

js所有的传递都是值传递