title: How to use response functions in Hosted Payment Form in Chase Paymentech?
body: <p>I am currently working on chase payment gateway integration with php. It has very bad documentation which does not shows how to use response functions on merchant parent page. I am using hosted payment form (HPF) in chase payementech. On the merchant parent page, I have response functions and iframe which contains hosted payment form. Here I don't know how to use response functions like </p>
  
  <pre><code>cancelCREPayment() 
  whatCVV2() 
  creHandleErrors(errorCode)
  creHandleDetailErrors(errorCode, gatewayCode, gatewayMessage)
  completeCREPayment(transaction) 
  </code></pre>
  
  <p>on the merchant parent page. I have submitted <code>callback_url</code>, <code>css_url</code> etc at the admin panel.</p>