Navigation Using rel

First published on 2006-07-19, updated on 2008-01-14.

The rel and rev attributes can be used on <link> and <a> to indicate relationships between documents:

<link href="/" rel="home" title="Homepage">
<a href="/" rel="home">Homepage</a>

These mean the resource at href is the homepage for the current document.


A few web browsers provide special UI for one or both forms. I’ve tried out 4 implementations.

Lynx 2.8.5

Automatically displays this navigation aid across the top of the page. All of the relationships appear as space-separated links which wrap across the top of the first page. You can jump to it from anywhere in the document by pressing the # key. Only supports <link rel>.

Opera 9.0

Go to View > Toolbars > Navigation to display it. You only get one button for each type and types which often have multiple entries are left out of the list.

Only supports <link rel>.

Uses buttons like Opera for most items. Has dropdown lists for rel values often applied to several links, such as chapter and bookmark. It groups some other items into a dropdown.

Supports <link rel> and <a rel>.

Uses a set of small toolbar buttons which have to be added to the toolbar using View > Toolbars > Customise. It can guess some relationships using URI structure or link text.

The most common navigation movements get individual buttons. A dropdown menu provides access to other link types, including any unrecognised values. It creates submenus when a rel value is applied to more than one link.

Supports <link rel> and <a rel>.

Standards Compliance

It seems <link rel> is more widely supported than <a rel>. Both use the link-types data type, so they have the same purpose.

Implementations should support both, like the Firefox add-ons?

Best Implementations

In my experience, here is what makes a special UI for rel useful:

Link Toolbar for Firefox is the best all-rounder, imho. They all do some things well, though.


Implementations which support rel on <a> enable authors to indicate relationships more efficiently. The relevant markup can be 70% smaller in both text/html and XML serialisations. Pages can look exactly as they did before.