A link provides a means of navigation from one resource to another. There are many everyday examples of links. Travelers use street signs and maps to decide which way to travel. Books and articles use footnotes and references to direct readers to related material. In software, we use variables and pointers to create links between different parts of an application.
The World Wide Web is based on the same principle. HTML documents
use anchors and forms to let users navigate between web pages, and they
to include references to related resources. Here is the body of a
representation of a resource as an HTML document:
<html> <head> <link href="http://www.restful-webservices-cookbook.org/styles/main.css" rel="stylesheet" type="text/css"/> <link href="http://www.restful-webservices-cookbook.org/feed" rel="alternate feed" type="application/atom+xml"/> </head> <body> <p><img src="http://www.restful-webservices-cookbookorg/images/cover" align="left"/>Read <a href="http://www.restful-webservices-cookbook.org"> RESTful Web Services Cookbook</a> to learn about building RESTful apps. </p> </body> </html>
link element in this example points to a related resource. A browser can
use the first
link element to discover the stylesheet
associated with this HTML document. A feed reader can use the second
link to fetch a related Atom feed. The
img element points to another related resource, an image file, that the browser can render on the screen. ...