Components are popular in web design as they provide a way to encapsulate frequently used functionality into pre-built structures and behaviours. These structures can then be easily customised using supplied options, or by directly editing the component itself. Web components are built using the basic building blocks of the web; HTML for structured data, CSS for visual rendering, and JavaScript for behaviour.
This example is hosted in a Nokia Developer Project, where you can find additional documentation, discover recent revisions, and contribute to the project.