Returns a string representing the platform of the browser.
platform = navigator.platform
platform is a string which must be an empty string or a string representing the platform on which the browser is executing.
For example: "MacIntel", "Win32", "FreeBSD i386", "WebTV OS"
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.