How can I create signature for AWS API in javascript usign HmacSHA256?

I'm trying to make a request to AWS API using Javascript, and starting with their examples provided here

I'm using hmac-sha256.js library for that too.

Here is the code:

    var today = new Date();
    time = today.toISOString();
    time = encodeURIComponent(time);

    var messageToEncrypt ="GET\nwebservices.amazon.com\n/onca/xml\nService=AWSECommerceService&AWSAccessKeyId=ACCESS&Operation=ItemLookup&ItemId=0679722769&ResponseGroup=SalesRank&Version=2013-08-01&Timestamp="+time;

    var sig = CryptoJS.HmacSHA256(messageToEncrypt, "MY SECRET KEY");

    var request = "http://ift.tt/1Ncnacm"+time+"&Signature="+sig;

I've used this library with the example which is provided in Amazon but I didn't get the same signature they provieded with dummy secrect access 1234567890

Am I missing something here?