Not sure which part of Javascript has the problem. To reproduce: At the top of the page, under "SØGEFORM": Switching between the two radiobuttons "Simpel søgning" and "Udvidet søgning" does not change the layout of the page. Try loading the page in Firefox and switch between the radiobuttons to see the correct behaviour.
(In reply to comment #0) This is because onfocus is used to trigger the reload function. Safari/Webkit doesn't support the focus event on input radio. I think that support for this event on all form elements should be added though.
Radio buttons are not mouse focusable on OS X. (Neither are buttons or checkboxes.) Whether or not they are keyboard focusable depends on the OS setting (and the focus event will fire in that case if full keyboard access is enabled).