how to show/hide divs by select.(jquery)

Answer 1

Wouldn't it be better to only hide the previously shown div? So;

var selection = 0;
$('#select').change(function() {
  $('#form' + selection).hide();
  selection = $(this).val();
  $('#form' + selection).show();
});

Do note that IDs should not start with numbers, but the above should do it.