[jQuery] How to extend an UI "class"?

[jQuery] How to extend an UI "class"?


For example if I would like to extend the progress bar, to write a
text...
I would extend some functions (like the initialization, and the value
setter functions) and I have to call super.function (except for the
text management calls)
How can I accomplish this?
(how to call super(...) how to excend an UI class?)
Thanks for the answers.