Just for fun : XSLT rotating banners

[Eric van der Vlist <vdv at dyomedea dot com>]

Hi,

I needed a rotating banners mechanism for prototyping a XML/XSLT based
site and I have been (again ;) amazed by the flexibility provided by XML
and XSLT (and xt's java extension since XPATH is missing a random
function)...

------------------- xml -----------------
<banners>
  <banner>
   <a href="/foo.xml" >
     <img src="/images/foo.png" border="0" alt="alt text"/>
   </a>
  </banner>
  <banner>
    <a href="/bar.xml">
       <img src="/images/bar.png" border="0" alt="alt text"/>
    </a>
  </banner>
</banners>
------------------- xsl -----------------
../..
  xmlns:math="http://www.jclark.com/xt/java/java.lang.Math"
../..
<xsl:template match="document-banner">
	<xsl:param name="cnt" select="count(/banners/banner)"/>
	<xsl:param name="rnd" select="math:random()"/>
	<xsl:param name="idx" select="round(($cnt -1) * $rnd) +1"/>
	<xsl:apply-templates select="/banners/banner[position()=$idx]/*"/>
</xsl:template>
------------------------------------------

I will probably not keep it for the production release (it would
probably scale very badly if you add more banners and, since my XML
Server dream is not yet implemented ;) I can't easily update a counter),
but it's allowing to rotate not only pictures but any XML snippet which
I find very flexible and convenient.

I hope you'll appreciate these lines as much as I have !

Eric
-- 
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Eric van der Vlist                                              Dyomedea

http://www.dyomedea.com                          http://www.ducotede.com
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