Printing only some properties of an object using for-in loop and if-else

I am wondering how to get only some of the elements of an object using only for-in and if-else.

For example, if we have the following object:

var person,
property;

person = {
    firstName: "John",
    lastName: "Smith",
    profession: "Lawyer",
    age: 31,
    eyeColor: "blue",
    hairColor: "blonde"
}

How do I print out only the second and fourth property of this object with for-in and if-else?