(function($){
  $.fn.checkgroup = function(options){
    //merge settings
    settings=$.extend({
      groupSelector:null,
      groupName:'group_name',
      enabledOnly:false
    },options || {});
    
    var ctrl_box=this;

    
    //allow a group selector override option
    var grp_slctr = (settings.groupSelector==null) ? 'input[name='+settings.groupName+']' : settings.groupSelector;
    
    //grab only enabled checkboxes if required
    if(settings.enabledOnly)
    {
      grp_slctr += ':enabled';
    }

    //attach click event to the "check all" checkbox(s)
    ctrl_box.click(function(e){
      chk_val=(e.target.checked);
      $(grp_slctr).attr('checked',chk_val);
      //if there are other "select all" boxes, sync them
      ctrl_box.attr('checked',chk_val);
    });
    //attach click event to checkboxes in the "group"
    $(grp_slctr).click(function(){
      if(!this.checked)
      {
        ctrl_box.attr('checked',false);
      }
      else
      {
        //if # of chkbxes is equal to # of chkbxes that are checked
        if($(grp_slctr).size()==$(grp_slctr+':checked').size()){
          ctrl_box.attr('checked','checked');
        }
      }
    });
  
  //JF init group check box
        //if # of chkbxes is equal to # of chkbxes that are checked
        if($(grp_slctr).size()==$(grp_slctr+':checked').size()){
          ctrl_box.attr('checked','checked');
        }
  
    //make this function chainable within jquery
    return this;
  };            
})(jQuery); 

   $(document).ready(function(){
    $('#includeRules').checkgroup({groupSelector:'.rulesGroup'});
    $('#includeTopics').checkgroup({groupSelector:'.topicsGroup'});
    $('#includeReferences').checkgroup({groupSelector:'.referencesGroup'});
    });