Sneakoscope is a Firefox extension that hides possible Harry Potter spoilers on the web. It's not perfect—if you visit Harry Potter websites or forums, it likely won't protect you completely. However, it should help avoid a random spoiler posted in a blog comment or news headline. Download Sneakoscope!

How does it work?
It's not magical. When a page has finished loading, elements with text that match a list of Potter-related words are colored green. You can click on these elements to see the text.
How do you configure it?
Sneakoscope is enabled by default, but you can easily disable it with a menu item it adds to Firefox's Tools menu. If you want to hack the regular expression it is using, take Firefox to about:config and search for "sneakoscope".
  • Sneakoscope can't hide all possible spoilers
  • Sneakoscope hides text after the page is fully loaded, so spoilers may be visible for a short time on long or slow-loading pages.
  • Sneakoscope can't hide text that is added to the page dynamically
  • Sneakoscope can't hide misspelled spoilers, for example: Vadermort is Hary's father!!!
  • Sneakoscope is English-only, though it could be adapted to other languages
  • Sneakoscope doesn't currently hide spoilers in page titles
  • Sneakoscope can't hide spoilers in images, audio, video, and other plugin content
  • This was written in a few hours and minimally tested, use at your own risk and remember to uninstall it when you've finished the book.