itemtypehttpsschemaorgPersonspan

Itemtype is an HTML attribute used in the microdata specification to declare the vocabularies that define the meaning of the annotated data on a web page. It is used alongside itemscope to mark an element as a structured item and with itemprop to label its properties. The itemtype value is a space-separated list of URLs identifying the vocabularies at hand; the first URL typically defines the item’s primary type, such as https://schema.org/Person, while additional URLs may refine or extend the vocabulary. When an element has itemscope and itemtype, search engines and parsers can map the marked properties to a semantic schema, enabling richer search results. A page may employ multiple vocabularies by listing more than one itemtype, though this is not common practice.

In practice, the properties of the item are defined using itemprop attributes on descendant elements; these properties should exist within the referenced vocabularies. Validation tools can check that the marked types and properties align with the vocabularies, and many crawlers rely on these annotations to interpret page content. Microdata, including itemtype, is one of several ways to embed structured data on web pages; others include RDFa and JSON-LD. Among these, JSON-LD is widely recommended by major search engines for its simplicity, but microdata remains supported by most crawlers and is still used in many sites.

Limitations include potential maintenance overhead and limited expressiveness for highly complex data structures. Developers choose among microdata, RDFa, and JSON-LD based on project needs, site architecture, and tooling compatibility, balancing ease of implementation with the desired level of semantic richness.