Use XSLT to generate RSS item description

RSS specifications do not allow HTML markup in title or description elements. If you want to include HTML markup in RSS elements, it has to be quoted, for example <b>bold</b>. Doing this in any server-side scripting language is easy, for example, ASP provides Server.HTMLEncode function. If you use XSLT to transform internal XML documents into RSS feeds, the task gets trickier, as XSLT provides no equivalent function.

The following XSLT templates solve the problem: call the outputQuotedTree template in the context of input node containing HTML markup and it will generate quoted contents of its child nodes.

<xsl:template name="outputQuotedTree">
  <xsl:for-each select="node() ¦ text()">
    <xsl:call-template name="outputTextNode" />
  </xsl:for-each>
</xsl:template>

 
<xsl:template name="outputTextNode">
  <xsl:choose>
    <xsl:when test="name() = ''">
      <xsl:value-of select="." />
    </xsl:when>
    <xsl:otherwise>
      <!-- Emit the opening tag -->
      <xsl:text>&lt;</xsl:text><xsl:value-of select="name()" />
      <!-- Emit the attributes of the opening tag -->
      <xsl:for-each select="@*">
        <xsl:text> </xsl:text>
        <xsl:value-of select="name()"/><xsl:text>='</xsl:text>
        <xsl:value-of select="."/>
        <xsl:text>'</xsl:text>
      </xsl:for-each>
      <xsl:choose>
        <xsl:when test="node() ¦ text()">
          <!-- If there are children, close the start tag and 
           process the children -->
          <xsl:text>&gt;</xsl:text>
          <xsl:for-each select="node() ¦ text()">
            <xsl:call-template name="outputTextNode" />
          </xsl:for-each>
          <!-- Emit the closing tag -->
          <xsl:text>&lt;/</xsl:text>
          <xsl:value-of select="name()" />
          <xsl:text>&gt;</xsl:text>
        </xsl:when>
        <xsl:otherwise>
          <!-- No children, emit the self-closing tag -->
          <xsl:text>/&gt;</xsl:text>
        </xsl:otherwise>
      </xsl:choose> 
    </xsl:otherwise>
  </xsl:choose>
</xsl:template>

 
</xsl:stylesheet>

Centering CSS-based layouts, Detecting text resize and more

The latest collection of links by Meryl Evans contains real gems:

• The article by Kris Hadlock has some great tips on creating CSS-based window-heigth or centered content.
• This article explains how to detect browser font size changes.
• CSS support in various browsers
• The anatomy of an RSS feed

MSXML firstChild property in VBScript

To complement a bit vague Microsoft MSDN document: firstChild property returns nothing (not null) if the XML node has no children. To test whether an XML node has children, use:

If Not (node.firstChild Is Nothing) Then ...

or, alternatively

If node.childNodes.length > 0 Then ...

Windows that resize to fit their content

This article contains a great description of JavaScript code that lets you resize a pop-up window to perfectly fit its content. Highly recommended!

Another way of writing less-than

In one of my projects, I had to check the version number of included JavaScript library to detect out-of-date browser cache. However, that's hard if you generate web pages with XSLT transformations. Finally, this trick worked for me - instead of writing

if (window.libraryVersion > minimumVersion) ...

... I wrote ...

if (Math.max(window.libraryVersion,minimumVersion) ==  minimumVersion) ...

Embedding JavaScript in XSL documents

Summary: Do not use complex inline JavaScript in XSLT-generated web pages

If you're using XSLT to produce full-blown (X)HTML pages from XML documents (more about that in one of my upcoming articles for www.InformIT.com), you'll sooner or later need a bit of inline JavaScript code in the final web page. As you know, you cannot use bare less-than-sign (<) in an XML document and you cannot use &lt; quoting in JavaScript embedded in <script> tags in traditional HTML page.

Apart from migrating all JavaScript code in a separate .js file (which is the best solution anyway) or using tricks to avoid < and & in the JavaScript code, the only way to make things work (at least in some modern XHTML-aware browsers) is to structure the web page to be XHTML-compliant with proper <!DOCTYPE> declaration and <html xmlns="http://www.w3.org/1999/xhtml"> root element.  When the browsers recognize a page as XHTML-compliant page, they might be willing to transform &lt; escape within the <script> tag into less-than sign (works for Opera, but not for Firefox).

Reading the XSLT-related standards, one would get an impression that using the <xsl:output method="html" /> command should force the transformation engine to write pure text instead of XML escapes within the <script> tag. However, it's almost impossible to force all the XSLT transformation engines being used today to do it properly (for example, it looks like MSXML engine on the IIS server simply ignores it).