xslt variable

        <p>
        You can build a variable by using select like below.
        </p>

        <pre data-sub="prettyprint:_">
        <xsl:variable name="v" select="xpath-expression" />
        </pre>

        <p>Or you can build a variable using constructor like below </p>

        <pre data-sub="prettyprint:_">
        <xsl:variable name="Subtotals">
        <!-- consturctor: can be any markup -->
        <xsl:for-each  select="Row">
        <number>
        <xsl:value-of select="Quantity * Price"/>
        </number>
        </xsl:for-each>
        </xsl:variable>

        <xsl:variable name="header">
        <h1 style="color:red;">This is demo</h1>
        </xsl:variable>

        <xsl:variable name="tmpResult">
        <xsl:apply-templates select="$orderRow" />
        </xsl:variable>
        </pre>

        <p>
        If a variable initialized by a select course, it contains a set of nodes. You can use the variable as a node. For example,
        </p>

        <pre data-sub="prettyprint:_">
        <xsl:variable name="books" select="//book"/>
        <xsl:for-each select="$books/author">

        </xsl:for-each>
        <!-- same as
        <xsl:for-each select="//book/author">

        </xsl:for-each>
        -->
        </pre>


        <p>If you are using constructor to build a constructor, the variable can hold any arbitrary content, this content is called result tree fragment. You can imagine a result tree fragment (RTF) as a fragment or a chunk of XML code. You can assign a result tree fragment to a variable directly, or result tree fragment can arise from applying templates or other XSLT instructions. The following code assigns a simple fragment of XML to the variable $author.  </p>

        <pre data-sub="prettyprint:_">
        <xsl:variable name="author">
        <firstname>Jirka</firstname>
        <surname>Kosek</surname>
        <email>jirka@kosek.cz</email>
        </xsl:variable>
        </pre>

        <p>Now let's say we want to extract the e-mail address from the $author variable. The most obvious way is to use an expression such as $author/email. But this will fail, as you can't apply XPath navigation to a variable of the type "result tree fragment."</p>


        <pre data-sub="prettyprint:_">
        <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
        xmlns:msxsl="urn:schemas-microsoft-com:xslt"
        extension-element-prefixes="exsl"
        version="1.0">
        ...
        <!-- Now we can convert result tree fragment back to node-set -->
        <xsl:value-of select="msxsl:node-set($author)/email"/>
        ...
        </xsl:stylesheet>
        </pre>

        <p>
        If you want to reuse the content of result tree, you can put copy-of statement to where you want your output to be.
        </p>


        <pre data-sub="prettyprint:_">
        <xsl:copy-of select="$header"/>
        </pre>