This page describes the Google Desktop Gadget API — the objects, methods, and properties you can use in your desktop gadgets. Unless otherwise noted, everything documented on this page has been available since Google Desktop 4. For a complete list of what changed in each release, see the Release Notes. For help on using the Gadget API, see Creating a Gadget.

Besides APIs defined by Google Desktop, your gadget can also use the core JavaScript API, the standard XMLHttpRequest class, and the W3C Level 1 DOM. For details, see APIs that a Gadget Can Use.

See For Detai Here http://code.google.com/apis/desktop/docs/gadget_apiref.html