function clear_form(f)
{
  var i_cnt, i_last, el ;
  i_last = f.elements.length ;

  for (i_cnt = 0 ; i_cnt < i_last ; i_cnt++)
  {
    el = f.elements[i_cnt] ;
    if (el.type == "text" || el.type == "textarea")
    {
      el.value = "" ;
      continue ;
    }
    if (el.type == "checkbox")
    {
      el.checked = false ;
      continue ;
    }
  }
  return ;
}