Addendum to my blogroll escapade

Posted May 18, 2025

Following on from setting up my blogroll last week, I’ve realised it doesn’t render as a pretty webpage in most web browsers. Serves me right for only testing in Firefox!

To style the document, I wrote the XLST in an xsl:stylesheet element with an id="blogroll" attribute. A processing instruction applies the stylesheet to the document.

<?xml-stylesheet type="text/xsl" href="#blogroll"?>

XML processors will look for the stylesheet by its ID, blogroll in this case. But when looking at an element, how do know if one of its attributes is an ID? The XML spec goes into detail about this.

In order for such an attribute value to be used as a fragment identifier in a URI, the XDM attribute node must generally have the is-id property […]. This property will typically be set if the attribute is defined in a DTD as being of type ID, or if is defined in a schema as being of type xs:ID.

Turns out, most processors need the ID attribute to be explicitly labelled. So I added the necessary document type declaration (DTD) explicitly specifying the ID attribute for xsl:stylesheet elements - in this case called id.

<!DOCTYPE OPML [<!ATTLIST xsl:stylesheet id ID #REQUIRED>]>

In Firefox’s case, the browser seems to assume id will be the ID attribute. As other browsers show though, that isn’t a safe assumption.

Anyway with a fix now in place, I hope you enjoy perusing my blogroll!