Date.prototype.formatString()

The formatString method has been added to the Date object. You can use it to format a date however you please. It takes one parameter that is a template for how you want the date to be formatted.
Below is a table of all the components you can use in your template to get the desired date format.

Template Part	Result Type
hh12	Current hour using 12 hour clock
0hh	Current hour using 24 hour clock
hh	Current hour
mmm	Three character month representation
0mm	Current minute
mm	Current minute
0ss	Current second
ss	Current second
AM or PM	Returns whether it is am or pm (uppercase)
am or pm	Returns whether it is am or pm (lowercase)
wYYYY	4 digit year
wYY	2 digit year
YYYY	4 digit year
YY	2 digit year
MMM	Full month title
0MM	Month number prefixed with 0 (if req)
MM	Month number
0WW	Week number prefixed with 0 (if req)
WW	Week number
DDD	Full day name
ddd	3 char day name
~0DD	Day number prefixed with 0 (if req)
DDth	Day number with correct suffix (th, rd, st)
DD	Day number

These can be combined to create your own date templates to use in your tiddlywiki. For example to display a date like, 27th January 2011 you'd need a template like:

var template = "DDth MMM YYYY";
date.formatString(template);

Or to display a date and time like, 27th Jan 18:54:23

var template = "DDth mmm hh:mm:ss";
date.formatString(template);