"date formats" and "ends-with"

(1) Date formats
I couldn't find information about date formats. How can you work with dates
in xpath ? Are there functions to help you translate one date format in
another ?

(2) ends-with
In xpath there is a function called "starts-with", is there als something
like "ends-with" ? I would like to check on the last character in the
string.

Could you help me solving these problems ?

Greetings,
Dineke van den Bos

dvdbos@ambrac.nl