Welcome to the XHTML Entity Network (XEN) Repository!

What is XEN?

XEN, pronounced zen, is a repository of relationships defined using the rel attribute of the <link> and <a> HTML tags (and also the <area> tag in HTML 5).

For example, the Business category defines the following relationships:

So, if you wanted to define a relationship to a vendor using a link you would use the following HTML markup:

You can view a list of all categories and relationships in the Repository and even download the current repository in XML format.

Why XEN?

There are a number of reasons why XEN came to exist:

• There is no single repository (or directory, if you prefer) that lists all the different relationships in one place and in a consistent manner
• There is a growing need to define numerous new relationships not currently covered by existing microformats, specifications or standards
• A simple categorisation scheme was required to make it easier to group and find similar relationships
• Some existing projects have rather dubious licensing and/or patenting terms and we wanted to highlight any issues to make it easier for developers and companies looking to adopt them

The objectives of the XEN repository are:

1. List all known relationsips, in logical categories
2. Provide an incubator for new relationships (and categories)
3. Clearly indicate the licensing and development status of all relationships
4. Promote unhindered discussion of relationships (but not marriage counselling )
5. Encourage all existing relationships to be fully open source
6. Provide an XML file containing all relationships, categories, licenses, etc.
7. Provide live-testing of some of the relationships here in the wiki