Hi I'm new in Javascript OO and want to know more about about inheritance. Hope you can provide some advice!

I see this great post: How to "properly" create a custom object in JavaScript?

which talks about how a class is inherited as I see in other websites, ex.:

function man(x) {
    this.x = x;
    this.y = 2;
}
man.prototype.name = "man";
man.prototype.two = function() {
    this.y = "two";
}
function shawn() {
    man.apply(this, arguments);
};
shawn.prototype = new man;

The above post claims that in order not to call "man"'s constructor while inheriting, one can use a helper like this instead:

function subclassOf(base) {
    _subclassOf.prototype= base.prototype;
    return new _subclassOf();
}
function _subclassOf() {};
shawn.prototype = subclassOf(man);

While I understand its intention, I don't see why we can't call

shawn.prototype = man.prototype;

I see it works exactly the same. Or is there something I'm missing? Thanks in advance!