One major difference between Navigator and Internet Explorer is that the "object model" (as Microsoft calls it) in Internet Explorer is not case-sensitive. Because IE can also be scripted with the non-case-sensitive VBScript language, all the HTML and browser objects such as Window, Document and Form are not case sensitive. Thus, in IE, you could write code that invoked DOCUMENT.WRITE() instead of document.write(). Don't expect code like this to work in Navigator, however! See Chapter 2, Lexical Structure, for details.