I am new to Sage Pay. I have received a customer requirement where we have replaced their legacy system to salesforce implementation and for payments module we have integrated salesfroce with SagePay and using it since a year. Now we have to implement 3D secure Sage Pay transactions for which we have got ACS url in response of transaction
 

{"statusCode":"2007","statusDetail":"Please redirect your customer to the ACSURL to complete the 3DS Transaction","transactionId":"49670F00-0DA0-C26F-FF2F-32D07728E08F","acsUrl":"https://test.sagepay.com/mpitools/accesscontroler?action=pareq …","paReq":"eJxVkt1uwjAMhe/3FKgP0PwVKMgEMWAaEp0Y7AW61BrVaClpWmBPv6S0Y9z52NYX+zgwvWSHXo26TI/5xGM+9abyCT72GnGxQ1VplBBhWcZf2EuTiccpC0aUjkaUDemQCT4Q1JOwmW3xJKEFScvxGZBOWoJW+zg3EmJ1el69yYCGfcGBtBIy1KuF7Ac0EIM+DYZiFAYhkFsa8jhD+V5ZQJWtMS6WNeamXKdZajAB0pRBHavc6KsM+QBIJ6DSB7k3phgTcj6f/dMNcrAQbCC+OvrVNxDXB+Q+56ZyUWm5lzSRYcX09hBtfz65LtggUvVLTfTSzBWdAHEdkMQGJXeuCM56jI+5GIshkCYPceYGkoxTSu3WNwWFe2T2UPqfAmu/xlx1O3UK8FIcczu9tA7+xZBgqeTOHWoTX3vRZmUfdykg92Xmr+4EylhXmXO/iRwvtWZxQUUDdAKI6yXtYUn7B2z08Dd+ARAvvW4=","status":"3DAuth"}

 as per the documentation  http://sagepay2013stg.prod.acquia-sites.com/content/using-3-d-secure
 
I have added this code in Vf page according to this, the above documentation
 
 <apex:page standardStylesheets="false" showHeader="False" sidebar="false" applyHtmlTag="true" CONTROLler="Test3DsecureCtrl" docType="html-5.0" id="pgId" >
 <form id="browserpost" method="POST" action="{!acsUrl}"> 
 <input type="hidden" name="PaReq" value="{!PaReq}"/>
  <input type="hidden" name="TermUrl" value="{!communitiesUrl}"/>
   <input type="hidden" name="MD" value="{!MDValue}"/>
  <input type="submit" name="Click Me" onClick="sendform()" id="btnid"/>
  </form> 
  <script> function sendform() { 
  alert('{!acsUrl}' ); 
  document.getElementById('pgId:browserpost:btnid').send();
  
  } 
  </script>      
</apex:page>

but this not working out, its not navigating me to any screen seems like its not compatible to vf
Any help or suggestions would be appericiated i am quite stuck on it.