Typing the tab character in browser text boxes

A lot of the time, when I want to format text within a web page's text box I'll hit the Tab key.

Unfortunately, that doesn't insert the tab character but instead moves the control to the next form element (like a button or a check box).

For browsers like Firefox/IE, is there a way to get the formatting behavior of a tab, within a text box, by typing a key combination?

Tabinta is a Firefox add-on that lets you do this.

In Windows, you can push Alt+09. This only works with the number pad number keys. (Release Alt after pressing the last number key.)

Linux and other POSIX systems (except Mac OS):

To input tabs in GTK+ applications (like Firefox or Chrome):

1. Ctrl + Shift + U

2. Type 9

3. Press Space or Enter

Source: Wikipedia: Unicode Input

In Safari and Firefox on Mac OS X, you can press ControlOptionTab to insert a tab in the text field you're currently editing.