About Subclassing in Javascript

Let the superclass be:

function Person(sex){alert('I am Person')}

and subclasses:

function Man(){this.sex='M'}
function Woman(){this.sex='F'}

The following two subclassing approaches don't seem to make any difference:

Man.prototype = new Person
Woman.prototype = new Person()
m = new Man()
w = new Woman()

In both cases:

• The function Person will be executed
• The constructor of both m and w are Person