I've got a shopping cart software.
I must send a JSON string that is produced following the user's payment.
I've this file .js :

var ProcessOrder = {

// Called when order is successful via PayPal
success : function(order, transactionId){
    $.info('Payment Success.  TransactionID: ' + transactionId);
    $.info('Order Data = ' + JSON.stringify(order));
    Ti.UI.createAlertDialog({
        title       : config.PAYMENT_SUCCESS_MESSAGE.TITLE,
        message     : config.PAYMENT_SUCCESS_MESSAGE.MESSAGE
    }).show();
},

// Called when order was cancelled by user during PayPal flow
cancelled : function(order){
    $.info('Payment Canceled');
},

// Called if an error occurs during PayPal transaction
failed : function(order, errorCode, errorMessage){
    $.info('Payment Error');
    $.info('errorCode: ' + errorCode);
    $.info('errorMessage: ' + errorMessage);
    alert(errorMessage);
}
};

The string that's produced following the order is:

$.info('Payment Success.  TransactionID: ' + transactionId);
$.info('Order Data = ' + JSON.stringify(order));

and consists of the particulars of the order.

I wish to send it by email or somewhere to ensure that I might understand what to transmit? Thanks ahead of time.

This code:

 $.info('Payment Success. TransactionID: ' + transactionId); 
 $.info('Order Data = ' + JSON.stringify(order));

creates JSON two strings:

 [INFO] Payment Success. TransactionID: AP-1YH922698A186825K   
 [INFO] Order Data = [{"itemID":"003","name":"Product","itemCount":1,"itemPrice":"2.50","totalPrice":2.5,"options":""}]

I wish to save this data inside a database or send email.

Publish transactionId and order JSON to PHP and parse JSON (http://php.internet/manual/en/function.json-decode.php) around the server-side. Or you will too Parse JSON on client-side and publish qualities you are looking at towards the php page. When you extract data in the JSON, it can save you it to database or send mail etc..