This is the stuff that makes my eyes bleed:
<FORM action="{$register_script_name}?{$smarty.server.QUERY_STRING}" method="POST" name="registerform"{if $js_enabled} onsubmit="javascript: if (check_zip_code(){if $default_fields.email.required eq 'Y'} && checkEmailAddress(document.registerform.email){/if}) return true; else return false;"{/if}>