object should not copy in javascript code example

Example 1: javascript copy an object without reference

var obj = {a: 25, b: 50, c: 75};
var A = Object.create(obj);
var B = Object.create(obj);

A.a = 30;
B.a = 40;

alert(obj.a + " " + A.a + " " + B.a); // 25 30 40

Example 2: make copy of object javascript

var x = {key: 'value'}
var y = JSON.parse(JSON.stringify(x))

//If you do not use Dates, functions, undefined, regExp or Infinity within your object