<xsl:attribute> Element

Article
02/21/2011

Creates an attribute node and attaches it to an output element.

<xsl:attribute
  name = "attribute-name"  
  namespace = "uri-reference">
</xsl:attribute>

Attributes

name
Required. The name of the attribute to create. If this value is a qualified name (QName), the attribute node is created in the namespace currently bound to the prefix, unless it is overridden by a namespace attribute. The value of the name attribute is interpreted as an attribute value template (expressions in curly braces are evaluated and converted to strings as in the <xsl:value-of> element). This allows the name of the attribute to be calculated or obtained from the source XML.

namespace
The namespace Uniform Resource Identifier (URI) of the created attribute. If the name attribute contains a QName, the prefix specified there will be bound to the namespace specified in the namespace attribute. This might result in the addition of other namespace declarations when serializing. This value is interpreted as an attribute value template.

Element Information

Number of occurrences	Unlimited
Parent elements	xsl:copy, xsl:element, xsl:fallback, xsl:for-each, xsl:if, xsl:message, xsl:otherwise, xsl:param, xsl:template, xsl:variable, xsl:when, xsl:with-param
Child elements	xsl:apply-imports, xsl:apply-templates, xsl:call-template, xsl:choose, xsl:copy, xsl:copy-of, xsl:fallback, xsl:for-each, xsl:if, xsl:message, xsl:number, xsl:text, xsl:value-of, xsl:variable

Remarks

The contents of this element specify the value of the attribute.

Attributes can be added or modified during transformation by placing the <xsl:attribute> element within elements that generate output, such as the <xsl:copy> element. Note that <xsl:attribute> can be used directly on output elements and not only in conjunction with <xsl:element>.

All attributes must be applied before children are added to the element.

Examples

This short example generates an attribute that obtains its value from the XML source. It generates output in the form <IMG src="value-from-XML-source"/>, using an XPath expression that retrieves the appropriate data from the XML source — here, "imagenames/imagename".

XSLT file

<IMG>
  <xsl:attribute name="src">
    <xsl:value-of select="imagenames/imagename" />
  </xsl:attribute>
</IMG>

Output

<IMG src=" imagenames/imagename"/>

While the <xsl:attribute> element can be extremely useful for dynamically creating output attributes that are not known prior to transforming a document, you do not need to use this element if you already know the attributes. In the preceding example, you might already know that an IMG element must contain a src attribute. Because you know this requirement prior to transforming the document, you would not have to use the <xsl:attribute> element. You could simplify the transformation syntax and still achieve the same result by using the following:

<IMG src="{imagenames/imagename}"/>

By using the <xsl:attribute> element instead of attribute value templates, you can:

Calculate the name of the attribute.
Use conditionals, templates, and attributes sets in conjunction with attribute generation.
Add attributes to an element generated by the <xsl:copy> or <xsl:element> element.

This section also contains the following full examples.

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