The body element, which is the beginning of the visible content of the document, expects content that consists of flow content. Flow content is less restrictive than other content categories and the HTML elements that belonging to the flow content category typically contain text or embedded content.

Elements belonging to the metadata content category modify the presentation or the behavior of the rest of the document, set up links to other documents, or convey other out of band information.

Phrasing content defines the text and the mark-up it contains. Runs of phrasing content make up paragraphs.

Elements belonging to the sectioning content model create a section in the current outline that defines the scope of <header/> elements, <footer/> elements, and heading content.

Heading content defines the title of a section, whether marked by an explicit sectioning content element or implicitly defined by the heading content itself.

Embedded content imports another resource or inserts content from another mark-up language or namespace into the document.

Interactive content includes elements that are specifically designed for user interaction.