function sort(aSortParam, aSortDirection)
{
  
  document.getElementById('sort').value = aSortParam;
 
  if(aSortDirection)
  {
    document.getElementById('sortDirection').value = aSortDirection;
  }
  else
  {
    document.getElementById('sortDirection').value = '';
  }
 
  document.forms.frmMethodRetrieval.submit();
}