[jQuery] Characters in a string

[Dave Maharaj :: WidePixels.com]

I have a string where i need to get the last specific number of characters
but cant seem to find an answer when you don't know the length of the
strings since its dynamic.
 
var str="/folder/subfolder/setfolder/6ab0e34e915";
 
where i need the last 11 digits (6ab0e34e915). The folder names change so
that number is never know to subtrct back from leaving me with 11
 
Any help would be great.
 
Thanks
 
Dave