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
[url] uses conditional comments that are supported by Microsoft Internet Explorer. They allow web developers to show or hide HTML code based on the version of the viewer's browser.
The DOCTYPE is a required preamble for HTML5 websites.
This page contains tags that are specific to an HTML 5 implementation.
The website claims HTML 4 Strict. HTML 4 extends HTML with mechanisms for style sheets, scripting, frames, embedding objects, improved support for right to left and mixed direction text, richer tables, and enhancements to forms, offering improved accessibility for people with disabilities.
The page shows content with an iframe; an embedded frame that loads another webpage.
JavaScript is a scripting language most often used for client-side web development.
The marquee element was first invented for Microsoft's Internet Explorer and is still supported by it. Other web browsers support it for compatibility with legacy pages. The element is non-compliant HTML