[spiralhead]

"but I think it was removed in as3"

Wrong. I was curious so i tested it (i've been experimenting with Flex 2). The following code outputs "blah blah":

var foo:Function = function() {}

foo.prototype.someMethod = function() { trace("blah blah"); }

new foo().someMethod();

I think the prototype syntax was kept to maintain backwards compatibility.

[ascw]

Thats cool, does it work with creating classes that way as well?

[spiralhead]

im assuming the above code is equivalent to:

class foo {

  public function someMethod() { trace("blah blah"); }

}

new foo().someMethod();

just different approaches to the same problem