/** 
 * Validate the selected product groups before posting it
 * Also validate the number of selected checkboxed in a form before posting it.
 **/
function validateCompareList()
{
  var elements = dojo.query("input[type=checkbox]", this);
  
  var selectedGroups = new Array();
  var teller = 0;
  for (var i=0; i<elements.length; i++)
  {
    if (elements[i].checked)
    {
      selectedGroups[teller] = productArray[elements[i].value];
      teller++;
    }
  }
  
  var group = '';
  for (var i=0; i<selectedGroups.length; i++)
  {
    if (group != '' && group != undefined && selectedGroups[i] != group)
    {
      alert('U kunt geen producten uit verschillende productgroepen met elkaar vergelijken ' + group + selectedGroups[i]);
      return false;
    }
    group = selectedGroups[i];
  }
  
  for (var i=0; i<elements.length; i++)
  {
    if (elements[i].checked)
    {
      return true;
    }
  }
  alert("Er zijn nog geen producten geselecteerd.");
  return false;
}

function initCompareList () {
  var p_forms = dojo.query('.productList');
  for (var i = 0; i < p_forms.length; i++)
  {
    p_forms[i].onsubmit = validateCompareList;
  }
}

initCompareList();