paypal request in ajax method

I'm making paypal request using Ajax calling but I'm getting error with status ZERO.The header format is JSON and data format is JSON. In header i send user ID,Password,Signature, app ID, IP address, request and response format, content type. In data i send return ur, receiver, cancel url , action type.

var dataObject = {};

  dataObject = {"returnUrl":"http://www.google.com","requestEnvelope":{"errorLanguage":"en_US"},"currencyCode":"USD","receiverList":{"receiver":[{"email":"tigs_87687_56@gmail.com","amount":"10.00"},{"email":"s1305010375_biz@gmail.com","amount":"10.00"开发者_高级运维}]},"cancelUrl":"http://www.igoogle.com","actionType":"PAY"};

var dataHeader = {};
    dataHeader = {"X-PAYPAL-SECURITY-USERID":"1301997553_biz_api1.gmail.com","X-PAYPAL-SECURITY-PASSWORD":"156497560","X-PAYPAL-SECURITY-SIGNATURE":"dfgdstergdfGZ3YxzVAglRLBF8nLVciVZVD7x5t4s7AArl","Content-type":"application/json","X-PAYPAL-DEVICE-IPADDRESS":"127.0.0.1","X-PAYPAL-REQUEST-DATA-FORMAT":"JSON","X-PAYPAL-RESPONSE-DATA-FORMAT":"JSON","X-PAYPAL-APPLICATION-ID":"APP-80W284485P519543T"};

 $.ajax({
    type:'POST',
    url:'https://svcs.sandbox.paypal.com/AdaptivePayments/Pay',//paypal url
    headers: JSON.stringify(dataHeader, null, 8),
    data: JSON.stringify(dataObject, null, 6),
    dataType:'json',
    success:onSuccess,
    error:function(xhr,ajaxOptions){
        alert(xhr.status + " :: "  + xhr.statusText);
                    }
       });

Have you tried viewing the http discussion between your browser and the server using something like Firebug? That should give you a better idea of what's going wrong.