The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook
Twitter cards make it possible for you to attach media experiences to Tweets that link to your content.
The DOCTYPE is a required preamble for HTML5 websites.
Defines the attributes of a web app in a simple JSON file. It describes how the web app should appear on the users system and how it should launch.
This page contains tags that are specific to an HTML 5 implementation.
A way to make Web content and Web applications more accessible to people with disabilities. It especially helps with dynamic content and advanced user interface controls developed with Ajax, HTML, JavaScript, and related technologies.
Adapting images for high-resolution and low-resolution displays.
The picture element provides images for different devices and is part of the HTML 5.1 specification.
The defer attribute gives a hint to the browser that the script does not create any content so the browser can optionally defer interpreting the script. This can improve performance by delaying execution of scripts until after the body content is parsed and rendered.
The description attribute provides a concise explanation of the page content.
Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. Its most common application is to style web pages written in HTML
JavaScript is a scripting language most often used for client-side web development.