>I can refer to

parent.document.frames["foobar"]

in my javascript, of course. Can I, and if so, how can I, get a reference to the same object hierarchy in my C# code-behind? TIA.

Just for any interested lurkers, I added a hidden variable to the parent document and then could refer to that in my javascript. Something like:

parent.document.frames["foobar"].window.document, "HiddenVar").value