Using XSLT search with multiple dropdowns

I've been modifying Douglas Robar's Umbraco XSLT search for a project where I need to filter a bunch of pages using some multiple dropdown lists. This is just a short description of how I've done it.

The scenario I have a bunch of nodes that are categorized using some multiple ddl datatypes. For example onde datatype "Season" with the values "Winter,Spring,Summer,Fall" and another "Theme" - "Theme1,Theme2,Theme3".

Now I want the user to filter all of my nodes by selecting some of the values. The tricky part is that if a node contains "Winter,Spring" and the user searches for "Spring,Summer" there should be a match.

I added a javascript function to the XSLT:

<msxsl:script language="JavaScript" implements-prefix="ps">
<![CDATA[
// Here is a lot of functions from the original XSLT

// My new function
function CompareParams(params, values){
  var par = params.split(",");
  var vals = values.split(",");
  var score = 0;
  var i = 0;
  for(i = 0; i < par.length; i++){
    var j = 0;
    for(j = 0; j < vals.length; j++){
       if(par[i] == vals[j]){
           score = score + 1;
       }
    }
  }
  if(values == ''){
    return true;
  } else {
    if(score > 0){
       return true;
    } else {
       return false;
    }
  }
}
]]>
</msxsl:script>

Then I added this to my Xpath:

<xsl:variable name="itemsSeason" select="$itemsRefined[ps:CompareParams(string(./data[@alias = 'season']),$season) = 'true'
and ps:CompareParams(string(./data[@alias = 'theme']),$theme) = 'true'
and @nodeTypeAlias = 'Aktivitet']" />

Creating the search form The next step was to create the search form using the datatypes. Luckily Umbraco has a neat little funtion for that. GetPreValues:

<xsl:template match="/">

<!-- start writing XSLT -->

<form action="?" method="GET">
  <select multiple="multiple" name="season">
  <xsl:for-each select="umbraco.library:GetPreValues('1042')/node()">
    <option>
       <xsl:attribute name="value">
           <xsl:value-of select="."/>
       </xsl:attribute>
       <xsl:if test="contains(umbraco.library:RequestQueryString('season'),./node())">
           <xsl:attribute name="selected">selected</xsl:attribute>
       </xsl:if>
       <xsl:value-of select="."/>
    </option>
  </xsl:for-each>
  </select>
  <select multiple="multiple" name="theme">
  <xsl:for-each select="umbraco.library:GetPreValues('1043')/node()">
    <option>
       <xsl:attribute name="value">
           <xsl:value-of select="."/>
       </xsl:attribute>
       <xsl:if test="contains(umbraco.library:RequestQueryString('theme'),./node())">
           <xsl:attribute name="selected">selected</xsl:attribute>
       </xsl:if>
       <xsl:value-of select="."/>
    </option>
  </xsl:for-each>
  </select>

  <xsl:variable name="searchstring" select="umbraco.library:RequestQueryString('search')" />
  <input type="text" name="search" value="{$searchstring}" />
</form>
</xsl:template>

I hope you all can use this :-)

Download the complete files here