Here are some useful tips as well.

// Just copies pointer to function into variable chr.
var chr = String.fromCharCode;
// Invokes function chr (String.fromCharCode) with the arguments in parenthesis.
var result = chr(Math.floor(224 + (code/16)));

I sometimes do this as well.

var $f=false;
var $t=true;
var $b=' ';
var $c = '\r\n';
var $n = null;

Note that $n works as 'null' is a special value of a JavaScript Object. You cannot do the same for keyword/value 'undefined'.