Dashboard is an application for Apple's Mac OS X operating systems, used for hosting mini-applications known as widgets. First introduced in Tiger, it is a semi-transparent layer that is invisible to the user unless activated by clicking its icon in the Dock. Alternatively, the user can invoke Dashboard by moving the cursor into a preassigned hot corner, or by pressing a hot key, both of which can be set to the user's preference.

When Dashboard is activated, the user's desktop is dimmed and widgets appear in the foreground. Like application windows, they can be moved around, rearranged, deleted, and recreated (so that more than one of the same Widget is open at the same time, possibly with different settings). New widgets can be opened, via an icon bar on the bottom of the layer, by dragging a widget icon out into the layer. After loading, the widget is ready for use.

Dashboard widgets are created using Hypertext Markup Language (HTML), Cascading Style Sheets (CSS) and JavaScript. Because the same languages are used for creating websites, many web developers can already build them. Widgets themselves are, at the core, simply HTML files that are displayed within the Dashboard layer; they use the WebKit application framework that is also used in Apple's Safari web browser, meaning even users running earlier versions of Mac OS X — where Dashboard is unavailable — can build them.

When a Dashboard widget is built, it usually consists of six files:
  • The widget's HTML file, which is the actual file that will be displayed in the Dashboard layer
  • The widget's CSS file, which is used for styling the widget (but is called on from the HTML file)
  • The widget's JavaScript file, although it may be implemented directly within the HTML file if the developer desires
  • The widget's Property List (called “Info.plist”), which is what Dashboard uses to load the widget’s properties (i.e.: name, version, HTML file, etc.)
  • The background image of the widget, in PNG format
  • The icon that is displayed in the menu bar
Once all of these files are in the root of a directory, it is given a name and the extension ".wdgt", and then it can be opened up in Dashboard as a widget. More complex widgets may also include a Cocoa widget plugin (for platform-specific functionality), one or more JavaScript files (for text scrolling, preferences, etc.) or multiple images (for personalized select menus or buttons).

Mac OS X v10.5 "Leopard" includes an application called Dashcode, which is a more user-friendly way of creating widgets. Another new feature of Mac OS X Leopard is called "Web Clips" which lets users easily create widgets from parts of a webpage. During the WWDC 2007 keynote, Steve Jobs made widgets out of the following: the featured news headlines on Yahoo.com, the top ten most searched terms on Google, the Photo of the Day on National Geographic, the Dilbert comic strip, and the box office information from Rotten Tomatoes. The user can also customize the border to further personalize the widgets.

Dashboard widgets, like web pages, are capable of many different things, often to perform tasks that would be tedious or complicated for the user to access manually. One example is the Google Search widget, which simply opens up the user's browser and performs a Google search. Other widgets, like Wikipedia, grab the contents of webpages and display them within Dashboard. Some widgets can also serve as games, using Adobe Flash (or another multimedia authoring program) to create games just as if they were in a browser.

Dashboard uses a variety of graphical effects for displaying, opening, and using widgets.[citation needed] For instance, a 3-D flip effect is used to simulate the widget flipping around, by clicking on a small i icon in the right bottom corner, the user can change the preferences on the reverse side; other effects include crossfading and scaling from icon to body (when opening widgets), a "spin cycle effect" when a widget is focused and the user presses Command-R or a suck-in effect[clarification needed] when they are closed. On sufficiently powered Macs, widgets will produce a ripple effect when they are opened, like a leaf falling onto water. These effects can be taxing and superfluous, consuming CPU resources, but with the help of OS X’s Quartz Extreme and Core Image graphics architectures, sufficient computing power to render them in real time is available. As with Exposé, Front Row and the minimise effect, holding shift down while calling the Dashboard or opening the Dashboard menu bar will display the effect in slow motion.

Although by default widgets are confined to the Dashboard layer, a widget can be dragged to the desktop by selecting the widget in the Dashboard shelf, dragging it, and then switching back to the desktop, from the Dashboard, before dropping the widget. (By default this is accomplished by pressing F12 on the keyboard, or F4 on Apple aluminum keyboards, to switch from desktop to Dashboard.) The widget will remain floating on the desktop until the next time the Dashboard is opened.

To keep one or more widgets on the desktop in a more permanent fashion, the Dashboard "devmode" must be activated. Enter the following into the Terminal:
  • defaults write com.apple.dashboard devmode YES
and then restart the Dock (and Dashboard):
  • killall Dock
After the devmode has been set, widgets dragged from the Dashboard will remain floating on the desktop, even after log out or shutdown. To move a desktop widget back to the Dashboard, simply reverse the process used to move it onto the desktop.