Learning javascript when I came across the concept of prototype. I succeeded in adding new methods to the **cat** class but failed in overriding the original **talk** method.

```
function cat(name) {
    this.name = name;
    this.talk = function() {
        alert( this.name + " : I'm a girl!" )
    }
}

cat.prototype.talk = function() {
    alert( this.name + " : I'm a dude!" )
}

cat1 = new cat("felix")
cat1.talk()

```

Why doesn't this alert the new text?