Thomas Wallace

Lectures and Resources

Microdata Overview

What is Microdata?

Microdata is a WHATWG HTML specification used to nest semantics within existing content on web pages.[1] Search engines, web crawlers, and browsers can extract and process Microdata from a web page and use it to provide a richer browsing experience for users. Microdata use a supporting vocabulary to describe an item and name-value pairs to assign values to its properties.[2] Microdata helps technologies such as search engines and web crawlers better understand what information is contained in a web page, providing better search results. Microdata is an attempt to provide a simpler way of annotating HTML elements with machine readable tags than the similar approaches of using RDFa and Microformats.

Global Attributes

  • itemscope – Creates the Item and indicates that descendants of this element contain information about it.
  • itemtype – A valid URL of a vocabulary that describes the item and its properties context.
  • itemid – Indicates a unique identifier of the item.
  • itemprop – Indicates that its containing tag holds the value of the specified item property. The properties name and value context are described by the items vocabulary. Properties values usually consist of string values, but can also use URLs using the a element and its href attribute, the img element and its src attribute, or other elements that link to or embed external resources.
  • itemref – Properties that are not descendants of the element with the itemscope attribute can be associated with the item using this attribute. Provides a list of id’s of elements with additional properties elsewhere in the document.

Example Formats – Schema.org