The <aside> Tag in HTML 5

The aside element is used for an HTML sidebar and is created using the <aside> tag, which is one of the sectioning tags in HTML 5. An <aside> separates content that departs from the theme of the main article, such as advertising, comments, an author's biography, background information on a news story or any other tangential content remotely related to the main article. The content in an aside element is less essential to the main text of an article than content in a figure element, which is usually referenced by the main article text.

For the main theme of an HTML document, the <article> tag is used. The <section> tag can be used to identify sections within an <aside> or <article>, such as the "Tag Summary", "Tag Syntax", "Element Attributes", "Tag Examples" and "What's New / Changes" sections on this page.