value type reference type object in javascript

Question

Are javascript objects value based or reference based? For example:

obj1.list =new array();
// ------ populate list
obj2.list = obj1.list

Answer 1

Javascript is based on reference semantics:

var a = [1,2,3];
var b = a;
a[0] = 42;
alert(b[0]); // will show 42
var c = a.slice(); // explicitly makes a copy
a[1] = 6502;
alert(c[1]); // will show 2, not 6502