An absolute link is a hyperlink containing a full URL, which includes all the information needed to find a particular site, page or document or other addressable item on the Internet.
This information includes:
- The protocol to use, such as HTTP (Hypertext Transfer Protocol) or FTP (File Transfer Protocol).
- The domain name of the site in which the sought-after item resides.
- The directory or subdirectory (directory within a directory) in the domain where the sought-after item resides.
- The file name of the item if applicable, often including the extension defining the type of item (HTML file, PDF file, image file, video, etc.).
Absolute links are invariably unique. That is, for any specific copy of a document or for any specific page or directory on the Web, there exists one and only one absolute link. Within a specific domain, absolute links are not always used by page authors because once a computer has found its way to a certain domain or directory, it does not need to have that domain or directory name specified again in order to locate the sought-after item.
Links are either absolute or relative. A relative link may consist of just a file name, because relative links only have to be unique within their domain or directory. When a relative link appears on a Web page, the browser understands that the file exists in the same domain or directory as the page itself. Relative links can be faster to load because the browser doesn’t have to start from scratch to find the site and then the content.