by value, by reference

gistfile1.js

// by value
var ref_1 = "string...";
var test_1 = ref_1;
ref_1 = "none";
console.log(test_1)

// by value : Wrapper Object (String, Number, Boolean)
var ref_2 = new String("hello world");
var test_2 = ref_2;
ref_2 = new String("world");
console.log(test_2)

// by reference
var ref_3 = new Array("one", "two", "three");
var test_3 = ref_3;
ref_3[0] = "1";
console.log(test_3)