var d = new Date();
var n = d.getFullYear();
Yes, n will give you the 4 digit year, but you can always use substring or something similar to split up the year, thus giving you only two digits:
var final = n.toString().substring(2);
This will give you the last two digits of the year (2013 will become 13, etc...)
If there's a better way, hopefully someone posts it! This is the only way I can think of. Let us know if it works!