Quoting from Cydget's description in Cydia:
Cydget is a flexible and powerful replacement system for WinterBoard Lock Widgets, allowing users to have multiple lockscreen displays active and to cycle between them. Developers and web designers can make "cydgets" using either native code or HTML with JavaScript and Cycript (a JavaScript superset that allows flexible access to Objective-C).
Cydget is built on Apple's "SpringBoard plugin" mechanism, so it does not conflict with other Apple-provided lockscreens, including VoiceRecorder and Nike+. However, some jailbreak lockscreen extensions are not compatible with Cydget, which may cause humorously overlapping displays if you have multiple lockscreen extensions active at the same time.
Some of Cydget's core benefits (over WinterBoard Widgets):
- configuration allows HTML scrolling
- multiple cydgets can be rotated
- they stop running when screen dims
- Cycript embedding for library calls
Unofficial documentation
Posts by JunesGraphics:
- What is a Cydget? - "Cydgets is Winterboard for Lockscreens...Cydgets opens up Lockscreens to more iPhone features. When HTML is run via winterboard it is run in a mobile view, also alot of features are not available. Things like Popups, Keyboards, EntryFields, LocalStorage, Fullpage views, and much more. These are available for us in Cydgets."
- Editing Winterboard Lockscreens to work with Cydgets
- Using keyboard for data in Cydgets
- Using LocalStorage with Cydgets
- Access to the camera roll and dealing photo binary data
- Editing any lockscreen to use image set from setbackground.cydget
- Cycript (links to this page explaining Cycript for Cydget makers)
- Running Cycript from Cydgets