penders - 4:16 pm on Mar 18, 2007 (gmt 0)

document.location.href=(Page + ".htm");

You need to use window.location.href or simply, location.href to change the page in the window, not document.location.

document.location (now deprecated in favour of document.url) is not the same as window.location.

document.location is supposed to be read only. However, Netscape (and it appears FF) allow this property value to be changed.