title: XSL if test display content when it has values
body: <p>I have an <code>if test</code> where I want to display the content of the 'year' property with a comma when the property has values. This isn't working so I would be thankful for suggestions.</p>
  
  <pre><code>&lt;xsl:if test="year != null"&gt;
       &lt;xsl:value-of select="year"/&gt;,
  &lt;/xsl:if&gt; 
  </code></pre>