In-place rot13 decoder.Decode rot13 in web pages. Just select the text, right click, and choose Rot13 from the menu. The translation appears right in the page, not in a pop up box. This preserves all formatting, including paragraph breaks, text styles, and links.
Or use it to encrypt text before you post. Type your plaintext into any input field, select it, and choose Rot13 from the right-click menu. The text will be encoded and ready to submit.