Meaning of Rel atttibute

Question

I found a strange a href in a webpage. It looks like

<a href=... rel="servername.com|6d63402c" ...other properties... ></a>

What does cryptic |6d63402c mean ? Is it a bitwise OR operation or just a string?

The document contains different links with different rels in this style.

Answer 1

The rel attribute specifies the link relationship type.

In HTML5 you may only use rel values that

• are defined in the HTML5 specification, or
• are registered in the Microformats wiki page existing rel values: HTML5 link type extensions.

As the value servername.com|6d63402c is not defined/registered, the page uses invalid markup.

As to what this specific value does: we can’t know (well, because it is not defined/registered). It’s probably some internal or third-party script that makes use of it. They should better use the data-* attribute instead of misusing rel.

Answer 2

Per the tag wiki: The rel attribute is used in HTML elements to specify the relationship and connection between the current document and the linked document.

Sources: W3C (link)

Source: W3Schools (link)