[zaa]

Try this one:

{* $Id: check_zipcode_js.tpl,v 1.2.2.2 2004/09/15 12:01:47 max Exp $ *}
<SCRIPT type="text/javascript" language="JavaScript 1.2">
var us_zip_code = '{$lng.txt_error_us_zip_code|replace:"'":"\'"}';
var ca_zip_code = '{$lng.txt_error_ca_zip_code|replace:"'":"\'"}';
{literal}
function check_zip_code_field(cnt, zip){
var alert_str;
   if(!cnt || !zip)
      return true;
   alert_str = '';
   if (cnt.options[cnt.selectedIndex].value=="US") {
      if (zip.value!="" && !(zip.value.length >=5 || zip.value.length <=9))
         alert_str = us_zip_code;
   } else if (cnt.value=="CA") {
      if (zip.value!="" && !(zip.value.length >=5 || zip.value.length <=9))
         alert_str = ca_zip_code;
   }

   if(alert_str.length > 0) {
      alert(alert_str);
      zip.focus();
      return false;
   } else
      return true
}
function check_zip_code(){
   return check_zip_code_field(document.forms["registerform"].b_country, document.forms["registerform"].b_zipcode) && check_zip_code_field(document.forms["registerform"].s_country, document.forms["registerform"].s_zipcode);
}
{/literal}
</SCRIPT>