function NextField(field, event)
{
 var keyCode = event.keyCode ? event.keyCode : event.which ? event.which : event.charCode;
 if (keyCode == 13)
 {
  var tas;
  for (tas = 0; tas < field.form.elements.length; tas++)
  if (field == field.form.elements[tas]) break;
  tas = (tas + 1) % field.form.elements.length;
  field.form.elements[tas].focus();
  field.form.elements[tas].style.backgroundColor="#C1CBD5";
  return false;
 } 
 else return true;
}