Different Colors for Alternating Rows

All,

I have bee using the following stylesheet to produce different colors for 
alternating rows whenever a row that has <td> tags without attributes or 
hyperlinks are encountered. The problem is for large documents the performance 
degrades significantly. This seems to be because in the algorithm used to 
calculate which color to use, a check is made to determine how many previous 
siblings have already been processed, so the number of checks grows 
exponentially as the number of rows grows.

It seems that that the same effect should be possible with greatly improved 
performance by recursively incrementing a variable whenever a row that is a 
candidate for a color change has been processed. I was unsure of how to go 
about doing this. Any code snippets would be greatly appreciated. Following is 
my stylesheets, sample HTML, and desire output:

Thanks,
Rechell Schwartz

<?xml version="1.0" encoding="iso-8859-1"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
                   version="1.0">
<xsl:output method="html" indent="yes"/>

<xsl:template match="node()|@*"> <!--identity transform-->
     <xsl:copy>
       <xsl:apply-templates select="node()|@*"/>
     </xsl:copy>
</xsl:template>

<xsl:template match="table/tr[td[not(a) and not(@class)]]">
        <xsl:copy>
     <xsl:choose>
     <xsl:when test="count( preceding-sibling::tr[td[not(a)  and 
not(@class)]] ) mod 2 = 1">
     <xsl:for-each select="td[1]">
      <td class="evenMedium" width="35%">
       <xsl:apply-templates select="node()|@*"/>
       </td>
      </xsl:for-each>
      <xsl:for-each select="td[2]">
      <td class="evenMedium" width="65%">
       <xsl:apply-templates select="node()|@*"/>
       </td>
      </xsl:for-each>
     </xsl:when>
     <xsl:otherwise>
     <xsl:for-each select="td[1]">
       <td class="oddMedium" width="35%">
       <xsl:apply-templates select="node()|@*"/>
       </td>
      </xsl:for-each>
       <xsl:for-each select="td[2]">
       <td class="oddMedium" width="65%">
       <xsl:apply-templates select="node()|@*"/>
       </td>
      </xsl:for-each>
     </xsl:otherwise>
     </xsl:choose>
       </xsl:copy>
</xsl:template>
</xsl:stylesheet>

The input file is:

<table>
<tr>
<td class="headerStyle" colspan="2">
Title
</td>
</tr>
<tr>
<td>Label1</td>
<td>Value1</td>
</tr>
<tr>
<td class="separatorStyle colspan="2">
---------------
</td>
</tr>
<tr>
<td>Label2</td>
<td>Value2</td>
</tr>
</table>

The desired output:

<table>
<tr>
<td class="headerStyle" colspan="2">
Title
</td>
</tr>
<tr>
<td class="oddRowStyle" width="35%">Label1</td>
<td class="oddRowStyle" width="65%">Value1</td>
</tr>
<tr>
<td class="separatorStyle colspan="2">
---------------
</td>
</tr>
<tr>
<td class="evenRowStyle" width="35%">Label2</td>
<td class="evenRowStyle" width="65%">Value2</td>
</tr>
</table>


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