Returns a string representing the platform of the browser.
platform = navigator.platform
platform is a string with one of the following values: "Win32", "Linux i686", "MacPPC", "MacIntel", or other.
Unless your code is privileged (chrome or at least has the UniversalBrowserRead privilege), it may get the value of the
general.platform.override preference instead of the true platform.
This was originally part of DOM Level 0, but has been since included in the HTML5 spec.