How to render html in XML with XSLT?

I am trying to render an html file using XSLT. The XSLT I am using is:

 <iframe>
                        <xsl:attribute name="href">
                          "sample.html" <!-- For testing -->
                        </xsl:attribute>
                      </iframe>

But when I open the xml file, it renders an empty iframe rather than the content of the sample.htm. What could be wrong ?