function navController()
{
  this.topContainer = $(arguments[0]); // box that holds nav list

  this.toggleTree = function() {
    var elem = $(arguments[0]);
    if (elem.style.display == 'none') {
      elem.style.display = 'block';
    }
    else {
      elem.style.display = 'none';
    }
//     Element.toggle($(arguments[0]));
    var img = $(arguments[1]);
    var imgSrcArray = img.src.split('/');
    var imgFile = imgSrcArray.pop();
    if (imgFile == 'box_plus.gif') {
      img.src = img.src.replace('box_plus.gif','box_minus.gif');
    }
    else {
      img.src = img.src.replace('box_minus.gif','box_plus.gif');
    }
  }
  
  this.hideInactive = function() {
    var nav_outer = this.topContainer.getElementsByTagName('ul');
    
    for (var i=0;i<nav_outer.length;i++) {
      if (Element.hasClassName(nav_outer[i],'active')) {
//         nav_outer[i].style.display = 'block';
        Element.show(nav_outer[i]);
      }
      else {
//         nav_outer[i].style.display = 'none';
        Element.hide(nav_outer[i]);
      }
    }
  }
  
  this.toggleVis = function() {
    var duration = arguments[1] ? arguments[1] : 1;
    if ( Element.visible($(arguments[0])) ) {
      Effect.BlindUp(arguments[0],{duration:duration});
    }
    else {
      Effect.SlideDown(arguments[0],{duration:duration});
    }
  }
  
}