[Jeremy Smith]

Its working sort of.

The alerts working when you go into put a deliberate incorrect format postcode like purely JH but its still allowing it through, here's the 2 tpl files I have used to make it work kind of:

File: /customer/home.tpl

<!-- POST CODE VALIDATION SCRIPT! -->

{literal}
<SCRIPT LANGUAGE="JavaScript">

function postit(){ //check postcode format is valid
test = document.registerform.b_zipcode.value; 
size = test.length;
 test = test.toUpperCase(); //Change to uppercase

 while (test.slice(0,1) == " ") //Strip leading spaces
  {test = test.substr(1,size-1);size = test.length;
  }
 while (test.slice(size-1,size)== " ") //Strip trailing spaces
  {test = test.substr(0,size-1);size = test.length;
  }
 document.registerform.b_zipcode.value = test; 
//write back to form field
 if (size < 6 || size > 8){ //Code length rule
  alert(test + " is not a valid postcode - wrong length");
  document.registerform.b_zipcode.focus();
  return false;
  }
 if (!(isNaN(test.charAt(0)))){ //leftmost character must be alpha character rule
   alert(test + " is not a valid postcode - cannot start with a number");
   document.registerform.b_zipcode.focus();
   return false;
  }
 if (isNaN(test.charAt(size-3))){ //first character of inward code must be numeric rule
   alert(test + " is not a valid postcode - alpha character in wrong position");
   document.registerform.b_zipcode.focus();
   return false;
  }
 if (!(isNaN(test.charAt(size-2)))){ //second character of inward code must be alpha rule
   alert(test + " is not a valid postcode - number in wrong position");
   document.registerform.b_zipcode.focus();
   return false;
  }
 if (!(isNaN(test.charAt(size-1)))){ //third character of inward code must be alpha rule
   alert(test + " is not a valid postcode - number in wrong position");
   document.registerform.b_zipcode.focus();
   return false;
  }
 if (!(test.charAt(size-4) == " ")){//space in position length-3 rule
   alert(test + " is not a valid postcode - no space or space in wrong position");
   document.registerform.b_zipcode.focus();
   return false;
   }
 count1 = test.indexOf(" ");count2 = test.lastIndexOf(" ");
 if (count1 != count2){//only one space rule
   alert(test + " is not a valid postcode - only one space allowed");
   document.registerform.b_zipcode.focus();
   return false;
  }
alert("Postcode Format OK");
return true;
}
</script>
{/literal}

<!-- END OF: POST CODE VALIDATION SCRIPT! -->

File: /customer/main/register.tpl

{* $Id: register.tpl,v 1.51.2.11 2008/04/03 10:34:21 joy Exp $ *}
{if $av_error eq 1}

{include file="modules/UPS_OnLine_Tools/register.tpl"}

{else}

{if $js_enabled eq 'Y'}
{include file="check_email_script.tpl"}
{include file="check_zipcode_js.tpl"}
{include file="generate_required_fields_js.tpl"} 
{include file="check_required_fields_js.tpl"}
{if $config.General.use_js_states eq 'Y'}
{include file="change_states_js.tpl"}
{/if}
{/if}

{if $action ne "cart"}

{if $newbie eq "Y"}
{if $login ne ""}
{assign var="title" value=$lng.lbl_modify_profile}
{else}
{assign var="title" value=$lng.lbl_create_profile}
{/if}
{else}
{if $main eq "user_add"}
{assign var="title" value=$lng.lbl_create_customer_profile}
{else} 
{assign var="title" value=$lng.lbl_modify_customer_profile}
{/if}
{/if}

{include file="page_title.tpl" title=$title}

<!-- IN THIS SECTION -->

{if $newbie ne "Y"}
{include file="dialog_tools.tpl"}
{/if}

<!-- IN THIS SECTION -->

{if $usertype ne "C"}
<br />
{if $main eq "user_add"}
{$lng.txt_create_customer_profile}
{else}
{$lng.txt_modify_customer_profile}
{/if}
<br /><br />
{/if}

{/if}
<font class="Text">

{if $newbie eq "Y"}
{if $registered eq ""}
{if $mode eq "update"}
{$lng.txt_modify_profile_msg}
{else}
{$lng.txt_create_profile_msg}
{/if}
{/if}
<br /><br />
{/if}

{$lng.txt_fields_are_mandatory}

</font>

<br /><br />

{capture name=dialog}

{if $newbie ne "Y" and $main ne "user_add" and ($usertype eq "P" and $active_modules.Simple_Mode eq "Y" or $usertype eq "A")}
<div align="right">{include file="buttons/button.tpl" button_title=$lng.lbl_return_to_search_results href="users.php?mode=search"}</div>
{/if}

{assign var="reg_error" value=$top_message.reg_error}
{assign var="error" value=$top_message.error}
{assign var="emailerror" value=$top_message.emailerror}

{if $registered eq ""}
{if $reg_error}
<font class="Star">
{if $reg_error eq "F" }
{$lng.txt_registration_error}
{elseif $reg_error eq "E" }
{$lng.txt_email_already_exists}
{elseif $reg_error eq "U" }
{$lng.txt_user_already_exists}
{/if}
</font>
<br />
{/if}

{if $error ne ""}
<font class="Star"><strong>
{if $error eq "b_statecode"}
{$lng.err_billing_state}
{elseif $error eq "s_statecode"}
{$lng.err_shipping_state}
{elseif $error eq "b_county"}
{$lng.err_billing_county}
{elseif $error eq "s_county"}
{$lng.err_shipping_county}
{elseif $error eq "email"}
{$lng.txt_email_invalid}
{elseif $error eq "username"}
{$lng.err_username_invalid}
{else}
{$error}
{/if}
</strong></font>
<br />
{/if}

<script type="text/javascript" language="JavaScript 1.2">
<!--
var is_run = false;
function check_registerform_fields() {ldelim}
    if(is_run)
        return false;
    is_run = true;
    if (check_zip_code(){if $default_fields.email.avail eq 'Y'} && checkEmailAddress(document.registerform.email, '{$default_fields.email.required}'){/if} {if $config.General.check_cc_number eq "Y" AND $config.General.disable_cc ne "Y"}&& checkCCNumber(document.registerform.card_number,document.registerform.card_type) {/if}&& checkRequired(requiredFields)) {ldelim}
        document.registerform.submit();
        return true;
    {rdelim}
    is_run = false;
    return false;
{rdelim}
-->
</script>

<form action="{$register_script_name}?{$smarty.server.QUERY_STRING|amp}" method="post" name="registerform" {if $js_enabled eq 'Y'}onsubmit="javascript: check_registerform_fields() + postit(); return false;"{/if}>
{if $config.Security.use_https_login eq "Y"}
<input type="hidden" name="{$XCARTSESSNAME}" value="{$XCARTSESSID}" />
{/if}
<table cellspacing="1" cellpadding="2" width="100%">
<tbody>
{include file="main/register_personal_info.tpl" userinfo=$userinfo}

{include file="main/register_billing_address.tpl" userinfo=$userinfo}

{include file="main/register_shipping_address.tpl" userinfo=$userinfo}

{include file="main/register_contact_info.tpl" userinfo=$userinfo}

{include file="main/register_additional_info.tpl" section='A'}

{if $config.General.disable_cc ne "Y"}
{include file="main/register_ccinfo.tpl"}
{/if}

{include file="main/register_account.tpl" userinfo=$userinfo}

{if $active_modules.Special_Offers and $usertype ne "C"}
{include file="modules/Special_Offers/customer/register_bonuses.tpl"}
{/if}

{if $active_modules.News_Management and $newslists}
{include file="modules/News_Management/register_newslists.tpl" userinfo=$userinfo}
{/if}

{if $active_modules.Image_Verification and $show_antibot.on_registration eq 'Y' and $display_antibot}
{assign var="antibot_err" value=$reg_antibot_err}
{include file="modules/Image_Verification/spambot_arrest.tpl" mode="advanced" id=$antibot_sections.on_registration}
{/if}

<tr>
<td colspan="3" align="center">
<br /><br />
{if $newbie eq "Y"}
{$lng.txt_terms_and_conditions_newbie_note}
{/if}
</td>
</tr>

<tr>
<td colspan="2"> </td>
<td>

{if $smarty.get.mode eq "update"}
<input type="hidden" name="mode" value="update" />
{/if}

<input type="hidden" name="anonymous" value="{$anonymous}" />

{if $js_enabled and $usertype eq "C"}
{include file="buttons/submit.tpl" type="input" style="button" href="javascript: return check_registerform_fields() + postit();  return false;"}
{else}
<input type="submit" value=" {$lng.lbl_submit|strip_tags:false|escape} " />
{/if}

</td>
</tr>

</tbody>
</table>
<input type="hidden" name="usertype" value="{if $smarty.get.usertype ne ""}{$smarty.get.usertype|escape:"html"}{else}{$usertype}{/if}" />
</form>

<br /><br />

{if $newbie eq "Y"}
{$lng.txt_newbie_registration_bottom}
<br /><a href="help.php?section=conditions" target="_blank"><font class="Text" style="white-space: nowrap;"><b>{$lng.lbl_terms_n_conditions}</b> </font>{include file="buttons/go.tpl"}</a>
{else}
{$lng.txt_user_registration_bottom}
{/if}

<br />

{if $is_areas.S eq 'Y' or $is_areas.B eq 'Y'}
{if $active_modules.UPS_OnLine_Tools and $av_enabled eq "Y"}
<br />
<br />
<br />
<table cellpadding="1" cellspacing="1" width="100%">
<tbody>
<tr>
<td colspan="3">
{include file="modules/UPS_OnLine_Tools/ups_av_notice.tpl" postoffice=1}
{include file="modules/UPS_OnLine_Tools/ups_av_notice.tpl"}
<br /><br />
</td>
</tr>
</tbody>
</table>
{/if}
{/if}


{else}

{if $smarty.post.mode eq "update" or $smarty.get.mode eq "update"}
{$lng.txt_profile_modified}
{elseif $smarty.get.usertype eq "B"  or $usertype eq "B"}
{$lng.txt_partner_created}
{else}
{$lng.txt_profile_created}
{/if}
{/if}

{/capture}
{include file="dialog.tpl" title=$lng.lbl_profile_details content=$smarty.capture.dialog extra='width="100%"'}

{/if}

Any suggestions?

Regards,
Jeremy