Links

A link, or hyperlink, is a reference from one document to another that can be followed by a user agent. On the Web, links are typically created with the HTML anchor element and point to a URL. The visible portion—the anchor text—may be plain text or an image. Links can link within the same site (internal) or to other sites (external). URLs can be absolute or relative; schemes such as http, https, mailto, tel, and fragment identifiers are common.

How a link works: when a user activates a link, the browser requests the target URL. If the resource is available, the server responds and the content is loaded. Links enable navigation, citation, and data integration across documents. They also support different link formats, such as text links and image links, and can include attributes like target, rel, and title to influence behavior and semantics.

History and implications: The idea of hypertext predates the Web; the Web popularized hyperlinks, formalizing them in HTML under Tim Berners-Lee. Links underpin search engines, which crawl the Web by following links to discover pages and assess relevance. Reliability and maintenance are concerns, as broken links (link rot) degrade user experience. Good anchor text helps comprehension and accessibility, and care is needed to avoid misleading links and to respect privacy and security considerations, such as using rel attributes for privacy or security when opening new tabs.

Beyond the Web, a link is a connection between nodes in a network or graph, called an edge. Links also appear as cross-references, citations, or identifiers in scholarly work. Shortened links compress long URLs for sharing but introduce dependability and trust issues.