This is the code for the CollapsedContents plugin.

<?php
<?php
 
class NP_CollapsedContents extends NucleusPlugin {
   var $itemid;
   var $catid;
 
   function getName() { return 'Collapse/Expand contents block'; }
   function getAuthor()  { return 'Andy'; }
   function getURL() { return 'http://matsubarafamily.com/blog/'; }
   function getVersion() { return '1.23'; }
   function getDescription() {
      return 'This plugin makes part of your contents collapse/expand. use <%collapse(sub_text)%> <%/collapse(sub_text2)%>';
   }
   function supportsFeature($what) {
      switch ($what) {
         case 'SqlTablePrefix':
            return 1;
         default:
            return 0;
      }
   }
 
   function install() {
      $this->createOption('scroll' , 'return to original position when collapsed', 'yesno', 'no');
   }
 
   function getEventList() { return array('PreItem'); }   
 
   function doSkinVar($skintype, $inout='',$comment='',$number=1) {
      $id = 'skin_' . $number;
      switch ($inout) {
         case '' :
echo <<<JSEND
<script language="javascript">
<!--
   function np_cc_showMore(id, showexpand){
      varexpand = ('np_cc_expand' + id);
      varcollapse = ('np_cc_collapse' + id);
      if( showexpand != 0 ) {
         document.getElementById(varexpand).style.display = "block";
         document.getElementById(varcollapse).style.display = "none";
      } else {
         document.getElementById(varexpand).style.display = "none";
         document.getElementById(varcollapse).style.display = "block";
      }
   }
 
//-->
</script>
JSEND;
         break;
         case 'in' :
echo <<<SKININ
<div id="np_cc_collapse$id" class="np_cc_switch_skin">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 1);return false;">$comment</a><br /></div>
<div id="np_cc_expand$id" style="display: none">
<div class="np_cc_skin">
SKININ;
         break;
         case 'out' :
         echo '</div>';
         if ($comment) {
            if ($this->getOption('scroll') == 'yes') {
echo <<<SKINOUTSCROLL
<div class="np_cc_switch_skin">
<a href="#np_cc_collapse$id" onclick="np_cc_showMore('$id', 0);return true;">$comment</a>
</div>
SKINOUTSCROLL;
            } else {
echo <<<SKINOUT
<div class="np_cc_switch_skin">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 0);return false;">$comment</a>
</div>
SKINOUT;
            }
         }
         echo '</div>';
         break;
         case 'togglein' :
         preg_match('/(.*)\|(.*)/', $comment, $match);
echo <<<SKINTOGGLEIN
<div id="np_cc_collapse$id" class="np_cc_switch_skin">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 1);return false;">{$match[1]}</a><br /></div>
<div id="np_cc_expand$id" style="display: none">
<div class="np_cc_skin">
<div class="np_cc_switch_skin">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 0);return false;">{$match[2]}</a>
</div>
SKINTOGGLEIN;
         break;
      }
   }
 
   function doTemplateVar(&$item, $inout, $comment,$number=1) {
      $id = $item->itemid . '__' . $number;
      switch (strtolower($inout)) {
         case 'in' :
echo <<<IN
<div id="np_cc_collapse$id" class="np_cc_switch">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 1);return false;">$comment</a><br /></div>
<div id="np_cc_expand$id" style="display: none">
<div class="np_cc_contents">
IN;
         break;
         case 'out' :
         echo '</div>';
         if ($comment) {
            if ($this->getOption('scroll') == 'yes') {
echo <<<OUTSCROLL
<div class="np_cc_switch">
<a href="#np_cc_collapse$id" onclick="np_cc_showMore('$id', 0);return true;">$comment</a>
</div>
OUTSCROLL;
            } else {
echo <<<OUT
<div class="np_cc_switch">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 0);return false;">$comment</a>
</div>
OUT;
            }
         }
         echo '</div>';
         break;
         case 'togglein' :
         preg_match('/(.*)\|(.*)/', $comment, $match);
echo <<<TOGGLEIN
<div id="np_cc_collapse$id" class="np_cc_switch">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 1);return false;">{$match[1]}</a><br /></div>
<div id="np_cc_expand$id" style="display: none">
<div class="np_cc_contents">
<div class="np_cc_switch">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 0);return false;">{$match[2]}</a>
</div>
TOGGLEIN;
         break;
      }
   }
 
 
    function replaceCallback($matches) {
      $id = $this->currentItem->itemid . '_' . $this->increment++;
      $expand = $matches[1];
      $collapse = $matches[3];
      if (preg_match('/(.*)\|(.*)/', $expand, $newmatch)) {
         $expand = $newmatch[1];
         $collapse2 = $newmatch[2];
      } else {
         $collapse2 = '';
      }
      $contents = $matches[2];
      $topswitch =<<<TOPSWITCH
<div id="np_cc_collapse$id" class="np_cc_switch">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 1);return false;">$expand</a><br /></div>
TOPSWITCH;
      if ($collapse2) {
         $toggleswitch =<<<TOGGLESWITCH
<div class="np_cc_switch">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 0);return false;">$collapse2</a>
</div>
TOGGLESWITCH;
      } else {
         $toggleswitch = '';
      }
      if ($collapse) {
         if ($this->getOption('scroll') == 'yes') {
         $bottomswitch =<<<BOTTOMSWITCHSCROLL
<div class="np_cc_switch">
<a href="#np_cc_collapse$id" onclick="np_cc_showMore('$id', 0);return true;">$collapse</a>
</div>
BOTTOMSWITCHSCROLL;
         } else {
         $bottomswitch =<<<BOTTOMSWITCH
<div class="np_cc_switch">
<a href="javascript:void(0)" onclick="np_cc_showMore('$id', 0);return false;">$collapse</a>
</div>
BOTTOMSWITCH;
         }
      } else {
         $bottomswitch = '';
      }
 
$s = <<<ALL
$topswitch
<div id="np_cc_expand$id" style="display: none">
$toggleswitch
<div class="np_cc_contents">
$contents
</div>
$bottomswitch
</div>
ALL;
        return $s;
    }
 
 
   function event_PreItem(&$data) {
      $this->currentItem = &$data["item"];
      $this->increment = 1;
      $this->currentItem->body = preg_replace_callback(
            '#<%collapse\((.*?)\)%>(.*?)<%/collapse\((.*?)\)%>#s',
            array(&$this, 'replaceCallback'),
            $this->currentItem->body
         );
      $this->currentItem->more = preg_replace_callback(
            '#<%collapse\((.*?)\)%>(.*?)<%/collapse\((.*?)\)%>#s',
            array(&$this, 'replaceCallback'),
            $this->currentItem->more
         );
   }
 
}
?>