[jQuery] Getting the highlighted text

[duggoff]

I have a textarea and a button that allows me to select some text and
apply a span and class to it. What I need to do is select that text
later and remove the span and class by clicking on a button. I think I
can handle to part that removes the span and class, but I don't know
how to get the selected text after I've highlighted it. Can anyone
help me?