Delete some remembered text from Browser TextBox in Windows you can put the curser on text box (focus on it) and push down arrow key ( down ) and the list of all text that textbox was remembered was shown, then you can move on them by up and sown arrow key and if press Delete on highlighted text it was removed but I can't do the same in my macbook pro. it doesn't have Delete key and this button act as BackSpace and it won't act if you press fn + Delete  . any one have any idea to delete remembered text in macbook-pro(os x).
It's shift + delete on windows.  In Firefox on my MacBook, shift + fn + delete does the trick.

Don't ask me why I know this.  That comment below Josh K's answer was totally hypothetical.