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 macOS — where Dashboard is unavailable — can build them. There is widget API allows the widgets to use Mac-specific interface elements such as the Apple Slider.