XSLT does not work when I include xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"

My Google sitemap renders well through XSLT fine without the xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" in the <urlset> element, however when included, my foreach statement doesn't work and nothing renders in the template

This is a FAQ.

XPath treats any unprefixed name as belonging to "no namespace". However, the elements in the provided document belong to the "http://www.sitemaps.org/schemas/sitemap/0.9" namespace -- not to "no namespace".

Therefore, the following XPath expression doesn't select any node at all:

urlset/url

Solution:

Define the "http://www.sitemaps.org/schemas/sitemap/0.9" namespace in the XSLT stylesheet and associate a prefix to it. Then use this prefix with all names that participate in any XPath expression.

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:s="http://www.sitemaps.org/schemas/sitemap/0.9"
 exclude-result-prefixes="s"
>

 <xsl:template match="/">
  <html>
    <body>
      <h2>Sitemap</h2>
      <table border="1">
        <tr bgcolor="#9acd32">
          <th>Location</th>
          <th>Last Modified</th>
          <th>Update Frequency</th>
          <th>Priority</th>
        </tr>
        <xsl:for-each select="s:urlset/s:url">
          <tr>
            <td><xsl:value-of select="s:loc"/></td>
            <td><xsl:value-of select="s:lastmod"/></td>
            <td><xsl:value-of select="s:changefreq"/></td>
            <td><xsl:value-of select="s:priority"/></td>
          </tr>
        </xsl:for-each>
      </table>
    </body>
  </html>
 </xsl:template>
</xsl:stylesheet>

when this transformation is applied on the provided XML document:

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    <url>
        <loc>{site_url}</loc>
        <lastmod>{current_time format="%Y-%m-%d"}</lastmod>
        <changefreq>monthly</changefreq>
        <priority>0.5</priority>
    </url>
</urlset>

it correctly produces the following result:

<html>
   <body>
      <h2>Sitemap</h2>
      <table border="1">
         <tr bgcolor="#9acd32">
            <th>Location</th>
            <th>Last Modified</th>
            <th>Update Frequency</th>
            <th>Priority</th>
         </tr>
         <tr>
            <td>{site_url}</td>
            <td>{current_time format="%Y-%m-%d"}</td>
            <td>monthly</td>
            <td>0.5</td>
         </tr>
      </table>
   </body>
</html>

the xpath will need the namespace as a prefix, eg

{http://www.sitemaps.org/schemas/sitemap/0.9}urlset

if it was xmlns:x="http://www.sitemaps.org/schemas/sitemap/0.9" you could use

x:urlset

it looks like this page will help http://msdn.microsoft.com/en-us/library/ms950779.aspx

EDIT: I was going to post that and follow up with an example of how to use xsl to define the prefix, but Dimitre already has.