xsl:attribute

Stylesheets can calculate attributes using xsl:attribute. Where xsl:value-of creates text, xsl:attribute creates attributes. The contents of the xsl:attribute element will become the value of the attribute. This differs from xsl:value-of which uses a select pattern to create text. Typically, the contents of an xsl:attribute will be a combination of text and xsl:value-of elements.

The following example creates a useful tag, the <box> tag. The contents of the tag are placed in an HTML table to format a box. The CSS style of the table is specified by an attribute in the source XTP. Tags like <box> are very useful examples of XSL. Instead of hard-coding HTML tables in a JSP file, the page can specify boxes. If the site wants to change the look, it's simple to change the stylesheet and modify the entire site at once.

default.xsl

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="box">
  <table>
    <xsl:attribute name="class">
      <xsl:value-of select="@class"/>
    </xsl:attribute>
    <tr>
      <td>
        <xsl:apply-templates/>
      </td>
    </tr>
  </table>
</xsl:template>

</xsl:stylesheet>

As mentioned above, the xsl:attribute uses xsl:value-of to compute the value of the @class attribute. The results below shows how much easier the XTP file will be when you use a <box> tag instead of creating the table directly.

hello.xtp
<box class="example"> This is an example. </box>

<table class="example"> <tr> <td>This is an example</td> </tr> </table>

StyleScript

The StyleScript equivalent for xsl:attribute uses name as its primary argument. The value of the attribute is defined within <<...>> tags as usual. The stylesheet shows how to combine text with the value-of expression.

default.xsl
$template(example) << <table> $attribute("class") <<$(@class)>> <tr> <td> $apply-templates(); </td> </tr> </table> >>

Summary

Tags in stylesheets are parsed, not raw text. So you can add attributes to elements.
xsl:attribute name="my-name"> adds an attribute to the current element.
$attribute(my-name) expands to xsl:attribute name="my-name".