XSLT RSS FEED - Combine substring-before and substring-after -

my apologies in advance if question simple, can’t seem find way around issue.

i need way combine substring-before , substring-after function in xsl have start , end point within description element of rss feed.

in each description tag want extract ‘primary title’ onwards, stop reaches first <b> tag.

i tried following xsl without success

<?xml version="1.0" ?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/xsl/transform"> <xsl:template match="channel"> <xsl:for-each select="item">   <xsl:value-of select=substring-after(description, 'primary title:' />  <xsl:value-of select=substring-before(description, '&ltb&gt' />    </xsl:for-each>  </xsl:template> </xsl:stylesheet> 

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below xml working with.

<rss version="2.0">   <channel>     <item>       <title>article_110224_081057</title>     <description> <![cdata[<div><b>description:</b>this description<b>primary title:</b>this primary title<b>second title:</b>this second title title </div> ]]> </description>     </item>     <item>       <title>article_110224_081057</title>        <description> <![cdata[<div><b>description:</b>this description<b>other title:</b>this other title<b>second title:</b>this second title titleb<b>primary title:</b>this primary title<b> more text </div> ]]> </description>     </item>   </channel> </rss>  

if <b> tag, won't able find using substring matching, because tags turned nodes parser. you'll able match substring if isn't tag, example because contained in cdata section (which appears case in example).