A parameter value must be passed by the immediately preceding template.

This is done by an xsl:with-param element as a child of xsl:apply-templates:

<xsl:apply-templates>
  <xsl:with-param name="name">value</xsl:with-param>
</xsl:apply-templates>

The bindings are only in effect for one template application.

The value can also be specified by a 'select' attribute.

The previous slide's example's call:

<xsl:apply-templates select="element">
  <xsl:with-param name="namespace">urn:publicid:IDN+...</xsl:with-param>
</xsl:apply-templates>