Extension attributes (XSLT only)

An extension attribute is an extra attribute on an XSLT-defined element. These attributes are all in the Saxon namespace http://saxon.sf.net/. This namespace needs to be declared in a namespace declaration, but it does not need to be listed in the extension-element-prefixes attribute.

For example, the saxon:assignable attribute can be set as follows:

<xsl:variable name="counter" saxon:assignable="yes" xmlns:saxon="http://saxon.sf.net/">

Like standard attributes in no namespace, extension attributes in the Saxon namespace can be prefixed with an underscore and used as shadow attributes (evaluated with a static expression). For example, saxon:_explain="{$EXPLAIN}", where $EXPLAIN is a global variable or parameter declared with static="yes".

The extension attributes provided with the Saxon product are as follows:

For the select attribute on xsl:when and xsl:otherwise, and the then and else attributes on xsl:if, see Experimental XSLT 4.0 extensions.