Hi Jen,
I'm deeply sorry to break this to you, but you are in fact using one of these old APIs. The Accept.js payment nonce can only be sent in a request to the current API.
To modify your code to the current API might not be as difficult as you think. You can check our API Reference for definitions and examples of the current API and its usage.
In your case, your current setup has an HTML form where the form field names match the field names that the request to our system is expecting. It's not quite as simple as just changing the field names in the HTML form, because requests to the current API are structured.
What may work best for you is to put some code into your script that takes the form fields that were posted, and then insert their values into sort of a "template" of a request in XML or JSON form. Here's a chunk of sample code that might get you started.
// make your "template"
$xmlStr = <<<XML
<?xml version="1.0" encoding="utf-8"?>
<createTransactionRequest xmlns="AnetApi/xml/v1/schema/AnetApiSchema.xsd">
<merchantAuthentication>
<name></name>
<transactionKey></transactionKey>
</merchantAuthentication>
<refId></refId>
<transactionRequest>
<transactionType>authCaptureTransaction</transactionType>
<amount></amount>
<payment>
<opaqueData>
<dataDescriptor>COMMON.ACCEPT.INAPP.PAYMENT</dataDescriptor>
<dataValue></dataValue>
</opaqueData>
</payment>
</transactionRequest>
</createTransactionRequest>
XML;
$post_string = new SimpleXMLElement($xmlStr);
// the following assumes you've put your credentials in somewhere
// as environment variables called "API_LOGIN_ID" and "TRANSACTION_KEY"
$loginId = getenv("API_LOGIN_ID");
$transactionKey = getenv("TRANSACTION_KEY");
$post_string->merchantAuthentication->addChild('name',$loginId);
$post_string->merchantAuthentication->addChild('transactionKey',$transactionKey);
// then insert some more code here to take your posted form fields and
// payment nonce and put them in the right part of the request in the
// same format.
// for example:
// $post_string->opaqueData->addChild('dataValue',$WhateverVariableHasThePaymentNonceInIt);
You'll need to change the URL endpoint to our new API's URL (https://apitest.authorize.net/xml/v1/request.api for sandbox). You'll also have to set the right Content-Type: header to use in the post request:
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/xml'));
Then, you'd just use curl to post the $post_string like before.
Let me know if you need any additional help.
