XSLT Reference

xsl:try

XSLT 3.0 element

Evaluates an XPath expression or sequence constructor and catches any dynamic errors, enabling graceful error handling in XSLT 3.0.

Syntax

<xsl:try select="expression"><xsl:catch .../></xsl:try>

Description

xsl:try is the XSLT 3.0 mechanism for catching dynamic errors that occur during transformation. Before XSLT 3.0, any error in an XPath expression or instruction aborted the entire transformation. With xsl:try you can isolate a risky operation, catch the error with a paired xsl:catch block, and either recover gracefully or emit a meaningful error message.

xsl:try works in two modes. In expression mode, you set the select attribute to an XPath expression whose value is returned if it succeeds. In instruction mode, you use a sequence constructor as the content of the element. Either way, if a dynamic error occurs within the try boundary, control transfers to the first matching xsl:catch sibling.

Common use cases include: calling extension functions that may fail, parsing user-supplied data that might be malformed, accessing documents that might not exist (doc() on an unknown URI), and converting strings to typed values where the cast may raise an error.

xsl:try does not catch static errors or type errors detected at compile time — only dynamic errors raised during evaluation.

Attributes

Attribute	Type	Required	Description
`select`	expression	No	XPath expression to evaluate. Mutually exclusive with content.

Examples

Safely parsing a date attribute

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<events>
  <event date="2026-03-15">Conference</event>
  <event date="not-a-date">Workshop</event>
  <event date="2026-04-01">Webinar</event>
</events>

Stylesheet:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="3.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/events">
    <results>
      <xsl:for-each select="event">
        <item name="{.}">
          <xsl:try select="format-date(xs:date(@date), '[D] [MNn] [Y]')">
            <xsl:catch>
              <xsl:text>Invalid date</xsl:text>
            </xsl:catch>
          </xsl:try>
        </item>
      </xsl:for-each>
    </results>
  </xsl:template>
</xsl:stylesheet>

Output:

<results>
  <item name="Conference">15 March 2026</item>
  <item name="Workshop">Invalid date</item>
  <item name="Webinar">1 April 2026</item>
</results>

Loading an optional document