Reports common JavaScript patterns for detecting
the browser or operating system in which script is being run. In addition
to pointing out non-portable constructs, these platform detection patterns
are often incomplete and easily fooled. For most cases, detection of individual
environment features is preferable to attempting to detect the entire platform.
Patterns detected include
document.all,
document.layers,
navigator.userAgent,
navigator.oscpu,
navigator.appName,
navigator.appCodeName, and
navigator.platform