Might be unrelated question, but does the actual page have a doctype? I'm unsure what IE6 and 7 do in Quirks Mode regarding JS, but if the page really does start with <html> (maybe you were making the code less verbose for us though), they are certainly in Quirks Mode.
What's the difference between the reset button and the default values button? If you start your boxes with default values in the first place (in the HTML), reset will display those.
You check to see if stuff ==false... if someone manually types in a 0, that's not false... is that okay?
You check to see if one of the two radio buttons has been selected... however, you will never know what user agent automatically chooses one or not, as the HTML specs say whenever you have a group of radio buttons, one must be checked="checked" at the start anyway. So, not choosing a radio button should never be an option. One should be checked by default anyway.