index.md

---

title: <xsl:key>
slug: Web/XSLT/Element/key

---

{{ XsltRef() }}

The <xsl:key> element declares a named key which can be used elsewhere in the stylesheet with the key( ) function.

Syntax

<xsl:key name=NAME match=EXPRESSION
  use=EXPRESSION />

Required Attributes

• name

  • : Specifies a name for this key. Must be a QName.

• match

  • : Defines the nodes for which this key is applicable.

• use

  • : Specifies an XPath expression that will be used to determine the value of the key for each of the applicable nodes.

Optional Attributes

None.

Type

Top-level, must be the child of <xsl:stylesheet> or <xsl:transform>.

Defined

XSLT, section 12.2.

Gecko support

Supported.