index.md

---

title: key
slug: Web/XPath/Functions/key

---

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The key function returns a node-set of nodes that have the given value for the given key.

Syntax

key( keyname, value )

Arguments

• keyname

  • : A string containing the name of the xsl:key element to be used.

• value

  • : The returned node-set will contain every node that has this value for the given key.

Returns

A node set.

Notes

• The xsl:key element defines what attribute on what given elements will be used to match the key.

This function is an XSLT-specific addition to XPath. It is not a part of the core XPath function library.

Defined

XSLT 1.0 12.2

Gecko support

Supported.