Modify jkpanel to load internal content instead of external content

Question

I am using an implementation of jkpanel in a vb.net app, the script (see below) loads an external file into the drop down panel. I need to modify this script to load an internal content like a specific div or span so that I can have this nested within the master page.

//Drop Down Panel script (March 29th, 08'): By JavaScript Kit: http://www.javascriptkit.com

var jkpanel={
 controltext: 'Panel Content',
 $mainpanel: null, contentdivheight: 0,

 openclose:function($, speed){
  this.$mainpanel.stop() //stop any animation
  if (this.$mainpanel.attr('openstate')=='closed')
   this.$mainpanel.animate({top: 0}, speed).attr({openstate: 'open'})
  else
   this.$mainpanel.animate({top: -this.contentdivheight+'px'}, speed).attr({openstate: 'closed'})
 },

 init:function(file, height, speed){
  jQuery(document).ready(function($){
   jkpanel.$mainpanel=$('<div id="dropdownpanel"><div class="contentdiv"></div><div class="control">'+jkpanel.controltext+'</div></div>').prependTo('body')
   var $contentdiv=jkpanel.$mainpanel.find('.contentdiv')
   var $controldiv=jkpanel.$mainpanel.find('.control').css({cursor: 'wait'})
   $contentdiv.load(file, '', function($){
     var heightattr=isNaN(parseInt(height))? 'auto' : parseInt(height)+'px'
     $contentdiv.css({height: heightattr})
     jkpanel.contentdivheight=parseInt($contentdiv.get(0).offsetHeight)
     jkpanel.$mainpanel.css({top:-jkpanel.contentdivheight+'px', visibility:'visible'}).attr('openstate', 'closed')
     $controldiv.css({cursor:'hand', cursor:'pointer'})
   })
   jkpanel.$mainpanel.click(function(){jkpanel.openclose($, speed)})  
  })
 }
}

//Initialize script: jkpanel.init('path_to_content_file', 'height of content DIV in px', animation_duration)
jkpanel.init('panelcontent.htm', '200px', 500)

Does anybody have any idea on how to modify this to do so or even have any tips or pointers to point me in the right direction to start doing so.

Cheers