Gadgets can be used to create daily status icons, such as Google Calendar's built-in weather calendar. They can be use to embed web pages that are associated with a given date, such as a movie showtimes calendar that displays trailers inside of each event's description. They can also be used to add new controls, such as the "Jump To Date" and "Next Meeting" features in Calendar Labs.
Google Calendar provides two APIs for embedding Calendars, which are described below.
Event Gadgets allow web content to be embedded within a calendar. This calendar can be specific to a single user, shared with many users. These events can appear as normal events, events with icons, or standalone icons without an event "chip". When clicked, the gadget will load a specified URL inside of an iframe instead of the normal event bubble.
Sidebar Gadgets are small, portable web applications that live in the left-hand side of the calendar UI. Supporting the gadgets.* API, these are an excellent choice whenever implementing complex functionality. They also have access to event data and Calendar user-interface controls, which also allows them to act as plugins for the Google Calendar interface.
Many of the Calendar Labs features are implemented as sidebar gadgets, including the "Jump To Date", "Next Meeting", and "World Clock" experiments. Additionally, existing Gadgets from other sites can often be converted into Sidebar Gadgets with little or no modification.