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XSLT Tutorial

XSLT Elements: xsl:for-each, xsl:attribute

xsl:for-each

• The xsl: for-each instruction allows you to do looping in XSLT for a given node set..  
  
• As we've seen from a previous example (Worksheet 4, people.xsl), these rows in a HTML table are processed for each person element in the people context:

<xsl:for-each select="PEOPLE/PERSON">
<TR>
    <TD><xsl:value-of select="NAME"/></TD>
    <TD><xsl:value-of select="ADDRESS"/></TD>
    <TD><xsl:value-of select="TEL"/></TD>
    <TD><xsl:value-of select="FAX"/></TD>
    <TD><xsl:value-of select="EMAIL"/></TD>
</TR>
</xsl:for-each>

xsl:attribute

The xsl:attribute allows you to add an attribute to an element.  This element is often used when you need to add a source(src) to an image.  Remembering that in HTML an img tag is still an element in XML term.  So when we are wanting to add any of these attributes to elements, you need to use this technique.

In this example we are adding a src attribute to an <img> tag:

<img>
  <xsl:attribute name="src">
  <xsl:value-of select="@src" />
  </xsl:attribute>         
</img>

The output:

<img src="dodaa.gif">
          

Tip:  If you find that the output goes over many lines then you can either:

• Place the code over one line:

<img><xsl:attribute name="src"><xsl:value-of select="@src" /></xsl:attribute></img>

• or do the following:

<img>
  <xsl:attribute name="src"><xsl:text/>
  <xsl:value-of select="@src" />
  </xsl:attribute>         
</img>

Attribute Value Template

Using the xsl:attribute element is useful when you want to output an attribute based on a choice (see the example in the xsl:choose section).

But if you want a simpler way to output an attribute for an element, you can use the Attribute Value Template, which uses curley brackets {} to surround the XPath expression that you want to ouput in an attribute.

Using the xsl:attribute element is a bit long, so, using the example above you can use the attribute value template to rather output:

<img src="{@src}" />

Attribute value templates can only be used with:

• <xsl:attribute>
• <xsl:element>
• <xsl:number>
• <xsl:processing-instruction>
• <xsl:sort>
• and of course all attributes (such as HTML attributes, img, etc) which do not belong to the XSL namespace.  

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