function getForm(num) {
    var zip     = $F("zip" + num );
    var pops    = "/form.php?zip=" + zip;
    var params  = "toolbar=yes,menubar=yes,location=yes,scrollbars=yes,resizable=yes,status=yes,";
    params     += "width=" + screen.width;
    params     += ",height=" + screen.height;
    params     += ",fullscreen=yes"
    window.open(pops, "", params);
  }

Event.observe(window, 'load', function() {
  if ($('submit1')) Event.observe('submit1',  'click', onZipSubmit );
  if ($('submit2')) Event.observe('submit2', 'click', onZipSubmit );
});

function onZipSubmit(e) {
  var btn  = Event.element(e).id;
  var num  = /\d+$/.exec(btn);
  var inpt = "zip";
  if (num) inpt += num;
  if (!/^\d{5}$/.test($F(inpt))){
    alert("Please enter a valid zip code.");
    Event.stop(e);
  }
}