javascript null or undefined or what

just couple of articles from the web that discuss in detail null/undefined  (results to be summarized sometime)

• http://constc.blogspot.com/2008/07/undeclared-undefined-null-in-javascript.html
• http://saladwithsteve.com/2008/02/javascript-undefined-vs-null.html
  • from comments in this post by a ‘Donovan West’, function isUndefined(x) {var u; return x === u;}