Public specification of a preferred URL for a page allows search engines to understand the original location for content.
Allows a website to define how a page is rendered in Internet Explorer 8, allowing a website to decide to use IE7 style rendering over IE8 rendering.
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook
The DOCTYPE is a required preamble for HTML5 websites.
The @font-face rule allows for linking to fonts that are automatically activated when needed.
This page contains tags that are specific to an HTML 5 implementation.
Adapting images for high-resolution and low-resolution displays.
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.
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 site generates a unique token when it makes the form page. This token is required to post/get data back to the server.
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
The description attribute provides a concise explanation of the page content.
JavaScript is a scripting language most often used for client-side web development.