Change The Values in a Form

Alright, I know how to change a value in a form on a document through javascript, but how do I change the value of a field in a form through a frame with javascript. I have to make a reference to the frame somewhere, right? Well, the frame with the field I want to change is named "Frame1", and the form on there is "Form1" and the field I wish to change is called "url".

Like this:
+---------------------------+
| |
| [Text Box Here] | <- Frame1
+---------------------------+
| |
| (JavaScript Here) | <- Frame2
+---------------------------+

I'm not sure how to change it from one frame to the other. Any help would be really REALLY appreciated.

I think parent.Frame1.document will get you Frame1's document object.. You know the rest

Thanks a lot!