Callbacks using blockchain.info's API I'm trying to accept bitcoin payments on my website using blockchain.info's API. However, I'm confused with their callback.

I've read through their callback, but how would I know if the transaction was successful or not ?
The callback lets you know the payment has been recieved. The confirmations are also included in the callback


  When a payment is received blockchain.info will notify the callback
  URL passed using the create method. The parameters will be supplied in
  a http GET request. The callback url is limited to 255 characters in
  length.
  
  Parameters
  
  
  value The value of the payment received in satoshi. Divide by    100000000 to get the value in BTC. 
  input_address The bitcoin address that received the transaction.
  confirmations The number of confirmations of this transaction.
  {Custom Parameters} Any parameters included in the callback URL will be passed back to the callback URL in the notification.
  transaction_hash The transaction hash.
  input_transaction_hash The original paying in hash before forwarding.
  destination_address The destination bitcoin address. Check this matches your address.
  
  
  A double spend occurs when a malicious user spends the same BTC twice.
  A payment that initial appears successful could be reversed at a later
  date. This is counteracted by waiting for the transaction to be
  included in the blockchain and reaching a number of confirmations. 6
  confirmations is generally considered safe for high value
  transactions.
  
  Validate the transaction confirmations in the callback script by
  checking $_GET['confirmations'] parameter. It is recommended you
  acknowledge the transaction at zero confirmations but only trust the
  transaction after one confirmation. For example, if purchasing a
  product, we would show the order as successful at zero confirmations,
  but only ship the product when 6 or more confirmations are reached.
  See the PHP demo callback.php for an example. 


sourced from: https://blockchain.info/api/api_receive