HTML and CSS Reference
THIS CHAPTER FOCUSES on how you can use advanced markup syntax to enable computer programs to under-
stand the data presented in your web pages. The web is full of structured data—the details of a local business, the
properties of an item for sale on an e-commerce website, or someone's profile information on a social networking site.
All of these examples follow a structured data model. The problem is that when this data is displayed on a web page,
it's difficult for computer programs to make sense of it. For a long time there was no set specification for how data
should be presented or how markup could be used to help make your web pages more meaningful to computer pro-
grams. Microdata changed this.
Microdata aims to bring structured data models into our web pages by enabling developers to define, use, and share
schemas that outline the structure of their data. Think of these schemas as templates of items. They define all the prop-
erties that an item could have. A simple schema for a human, for example, would have properties such as height,
weight, eye color, hair color, and age.
Enabling computer programs to extract data from your web pages opens up a realm of new possibilities to developers.
It allows developers to build web applications that can interact with each other without necessarily needing to know
the specifics of how the other application is built. For example, Google has already started looking for microdata when
it crawls web pages and will often display this data alongside a website in the search results if it thinks that the data
might be relevant to the user's search. Google is currently doing this for local businesses, products, and reviews, and
plans to expand on this in the future.
Microdata is still in its infancy and therefore a lot of possible applications for this technology have not even been
thought about yet. In this chapter you are going to learn how you can use microdata to mark up local businesses,
events, people, and products to make them more visible to search engines.
Microdata will only truly succeed in enabling computer programs to make sense of the data in your web pages if the
schemas that you use when defining your items are consistent. This problem has been recognized by some of the
world's largest search engines, many of which are already using microdata in order to display better results to their
users. Schema.org is a collaborative effort between Bing, Yahoo!, Google, and Yandex to come up with a set of con-
sistent schemas that developers can use to mark up their structured data.
Many schemas have been developed by the contributors to the schema.org project. In this chapter, you learn about the
schemas that you will be using most frequently: LocalBusiness, Event, Person, and Product.
You can find a full list of schemas on the schema.org website: http://schema.org/docs/full.html .