Displaying a text box

Can anyone tell me how to do this:

I have a selection list. If the user selects a particular entry I want a pop-up window to appear. This window contains a text box that the user can enter information into. When the form is submitted the page that generated the window needs to add the new value into the selection list.

I know how to make the new window pop-up using javascript, I also know how to add the new option to the selection list. I don't know how to transfer the submitted form back to the calling page.

Anyone help - or is there a better way of doing this??

Thanks

HD

Don't worry I've stumbled across window.prompt() which is OK.

However, if anyone has any better methods I'd be grateful.

Thanks

HD