Hacking the web with Greasemonkey

Simon Willison

Web technologies enthusiast

http://simon.incutio.com/

In the beginning...

• ... there were bookmarklets
• Bookmarks with embedded JavaScript
• Execute in the scope of the current page
• Lots of neat tricks, a few frustrating limitations

Wouldn't it be cool if...

• ... you could set a bookmarklet to execute automatically when you visit a specific site?
• Enter Greasemonkey

User scripts

• Greasemonkey enables the creation and sharing of user scripts
• Scripts can be configured to run on specific sites, or every site you visit
• It's easy to share scripts you've written with other people
• Customise the web, one site at a time

Examples

• Wikipedia Search - fixing minor annoyances
  • Simple site specific customisation
• Odeon - fixing broken sites
  • Patches for the web
• Gmail Persistant Searches
  • Adding new features!

The Killer App

• Customising corporate web applications
• Productivity hacks can be shared
• Even simple things like pre-filling a form field make life more pleasant

Greasemonkey adoption

• Nearly 600 user scripts shared so far
• Flickr changed their interface
• Someone lost their job!
• Opera and IE are getting user scripts as well
• The first Greasemonkey book is on the way

Words of warning

• Unfrozen APIs
• Malicious scripts
• User assumptions
• User Scripts are hacks

Getting started

• Install Greasemonkey: http://greasemonkey.mozdev.org/
• Try out some user scripts: http://dunck.us/collab/GreaseMonkeyUserScripts
• Learn to write your own: http://diveintogreasemonkey.org/
• Google:
  • greasemonkey
  • greasemonkey "user scripts"
  • bookmarklets
• Any questions?