xslt-lab/site/content/xslt/functions/xpath-system-property.md

title, description, date, version, versionLabel, category, syntax, tags

title	description	date	version	versionLabel	category	syntax	tags
system-property()	Returns the value of a named XSLT system property such as the XSLT version, vendor name, or vendor URL.	2026-04-18T00:00:00Z	1.0	XSLT 1.0	node function	system-property(name)	xslt reference xpath xslt1

Description

system-property() returns the value of a named system property from the XSLT processor. The argument is a QName that identifies the property. Properties in the xsl: namespace are defined by the XSLT specification; processor vendors may expose additional properties in their own namespaces.

The three standard XSLT 1.0 properties are:

Property name	Type	Description
xsl:version	number	The XSLT version supported by the processor (e.g. 1 or 2).
xsl:vendor	string	A string identifying the XSLT processor vendor.
xsl:vendor-url	string	A URL with more information about the vendor or processor.

If an unknown property name is passed, system-property() returns an empty string.

The function is most commonly used for version detection: testing whether the processor supports XSLT 2.0 so that the stylesheet can adapt its behaviour accordingly.

Parameters

Parameter	Type	Required	Description
name	xs:QName	Yes	The name of the system property to retrieve.

Return value

xs:string or xs:number — the property value, or "" for unknown properties.

Examples

Display processor information

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<doc><title>System Info</title></doc>

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/doc">
    <processor-info>
      <version><xsl:value-of select="system-property('xsl:version')"/></version>
      <vendor><xsl:value-of select="system-property('xsl:vendor')"/></vendor>
      <vendor-url><xsl:value-of select="system-property('xsl:vendor-url')"/></vendor-url>
    </processor-info>
  </xsl:template>
</xsl:stylesheet>

Output (Saxon example):

<processor-info>
  <version>2</version>
  <vendor>Saxonica</vendor>
  <vendor-url>http://www.saxonica.com/</vendor-url>
</processor-info>

Adapt behaviour based on XSLT version

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<data><value>3.14159</value></data>

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/data">
    <result>
      <xsl:choose>
        <xsl:when test="system-property('xsl:version') &gt;= 2">
          <!-- XSLT 2.0+ features available -->
          <formatted><xsl:value-of select="format-number(value, '0.00')"/></formatted>
        </xsl:when>
        <xsl:otherwise>
          <!-- XSLT 1.0 fallback -->
          <formatted><xsl:value-of select="value"/></formatted>
        </xsl:otherwise>
      </xsl:choose>
    </result>
  </xsl:template>
</xsl:stylesheet>

Output:

<result>
  <formatted>3.14</formatted>
</result>

Notes

• system-property('xsl:version') returns a number, not a string. Use numeric comparison (>= 2) rather than string comparison (= '2').
• For unknown property names, the return value is "" (empty string), not an error.
• Vendor-specific properties must be referenced using a namespace prefix that maps to the vendor's extension namespace.
• In XSLT 2.0+, the same function is available with the same three standard properties. Processors may report xsl:version as 2 or higher. The XSLT 3.0 specification also defines this function identically.

See also

• element-available()
• function-available()