[flexcoders] Question on how to find out what something is.

[timgerr]

So I have this form
<mx:Form id="One">
  <mx:FormItem label="First">
     <mx:TextInput id="first"/>
  </mx:FormItem>
</mx:Form>

so I have this function 
init():void
{
  trace(One.getChildren().length)
}

My question is what is One, what kind of component or object is it. 
This is what I mean;

I take the same form and add a creationcomplete to it:
<mx:Form id="One" creationcomplete="init(somthing)">
  <mx:FormItem label="First">
     <mx:TextInput id="first"/>
  </mx:FormItem>
</mx:Form>

In the above example I pass something into init (init(something), what
is that something?  I am not sure how to declare it?

init(this:NotSureWhatItIs)
{
  trace ???
}

If I do an object I do not have access to getChildren().

What do I do?
Thanks for the help
timgerr