XML Tutorials - Herong's Tutorial Examples - Version 5.05, by Dr. Herong Yang
"value-of" - Evaluating XPath String Expressions
This section describes the 'value-of' element, which is used in the content of a 'template' element. The 'value-of' element is an XSLT statement that evaluates an XPath expression into a string.
"value-of": A child element used as part of the content of a "template" element. An "value-of" element serves as an XPath string expression evaluation statement. The syntax of the "value-of" element is:
<xsl:value-of select="expression"/>
where "expression" is an XPath expression that produces a string.
When an expression of non-string datatype is used, its final value will be converted into a sting using these rules:
For example, the following template is defined with a "value-of" element:
<xsl:template match="p"> <xsl:value-of select="3 * 3"/>; <xsl:value-of select="@a"/>; <xsl:value-of select="c"/> </xsl:template>
To test the above template, I wrote this source XML document:
<p a="v"> Some text with a <c>child <d>element</d></c>. </p>
If the above template is applied, the transformation engine will match the element "p" in the source XML document with the defined template. Then the transformation engine will evaluate 3 XPath expressions and generate this output:
9; v; child element
Last update: 2014.
Table of Contents
Introduction of XML (eXtensible Markup Language)
DOM (Document Object Model) Programming Interface
SAX (Simple API for XML) Programming Interface
DTD (Document Type Definition) Introduction
Validating an XML Document against the Specified DTD Document Type
XSD (XML Schema Definition) Introduction
Validating XML Documents Against Specified XML Schemas
XSL (Extensible Stylesheet Language) Introduction
XSLT (XSL Transformations) Introduction
►XSLT Elements as Programming Statements
►"value-of" - Evaluating XPath String Expressions
Examples of Using "value-of" Elements
"{expression}" - Shorthand of "value-of" Elements
"variable" - Declaring Variables
"for-each" - Looping through a Node Set
Examples of Using "for-each" Elements
"if" - The Conditional Element
"choose" - The If...Else Element
Control and Generate XML Element in the Result
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