how to change object property value in javascript

var data = {
    'PropertyA': 1,
    'PropertyB': 2,
    'PropertyC': 3
};

data["PropertyD"] = 4;

// dialog box with 4 in it
alert(data.PropertyD);
alert(data["PropertyD"]);var object = { boo:true, baa:5 };
console.log(object);
function change() {
  object.boo = false;
  object.baa++;
};
change();
console.log(object);
//Hope this helps!myObject.sProp = 'A new string value for our original string property';