> But , unfortunately , the string included in the tag <taghtml> is 
> treated as a string , not as HTML code

No.

If the input is as you show, the content of taghtml will be a tree
consisting of

text node (white space)
a element node
  attribute node href
  attribute node class
  attribute node target
  text node Politecnico di Torino
text node (white space)

If your template for taghtml does
<xsl:copy-of select="node()"/>
then that HTML tree fragment will be copied to your result tree.

If you are seeing < appearing in teh browser then your input must b

<taghtml><![CDATA[ <a href= "http://www.polito.it" class="norm" 
target="_top">Politecnico di Torino</a> ]]></taghtml>

In this case the content of taghtml is a single text node containing the
string 

<a href= "http://www.polito.it" class="norm" 
target="_top">Politecnico di Torino</a>

David

  

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