how to disable the key using jquery when the page is been loaded?

how to disable the key using jquery when the page is been loaded?

I have downloaded a jquery numeric keypad plugin from the link
http://keith-wood.name/keypad.html . Now i want to disable a key when the
page is been loaded. I tired in all ways but i din get any solution . The
key should be disabled once the page is been loaded .
Thanks in Advance.