For any use of the xsl:param element, there is a region of the stylesheet tree within which the binding is visible. This region includes the siblings that follow the xsl:param instruction together with their descendants. Within this region, any binding of the parameter that was visible on the xsl:param element itself is hidden. Thus, only the innermost binding of a parameter is visible. The set of parameter bindings in scope for an expression consists of those bindings that are visible at the point in the stylesheet where the expression occurs.

The xsl:param instruction can be a top-level element. If it is, it declares a global parameter that is visible to the entire stylesheet. When the XSLT processor evaluates the select or expr attribute in a top-level xsl:param instruction, the current node is the root node of the document.

Passing parameters to templates