copying xhtml between windows

Hi again

I am using
window.opener.inputform.body.value=frames[0].objContent.DOM.body.innerHTML

to copy the content of the editor between two windows. It works fine, but I would like to transfer the xhtml version of the content instead. I have messed around trying to use getXtml, etc., but can't seem to get the syntax right. What I want to do is click on a button in the editor window and have the xhtml content transfer from the editor to a form field in the opening window. Any clues anyone?
Thanks