Q:

Display and or use form fields in ColdFusion that are invalid if you just try and wrap them with pound signs

I am posting in ajax an object called trxdetails to a cfm page.
// onAuthorize() is called when the buyer approves the payment
            onAuthorize: function(data, actions) {
                return actions.payment.get()
                        // PayPal Info
                        .then( function (paypalinfo) { 
                            console.log(paypalinfo)
                        })
                        // Execute Payment
                        .then(actions.payment.execute)
                        // Transaction Details
                        .then( function (trxdetails) { 
                            console.log(trxdetails)

                            $.ajax({
                              url: 'PayPalExpress/ajax_trxdetails.cfm',
                              type: 'post',
                              data: trxdetails,
                              success: function(json) {
                                console.log(json)
                              }
                            });

                        })
                        //.then(trxdetails => console.log(trxdetails));
            }

When I cfdump form, I get these field names:

ID,INTENT,STATE,CART,PAYER[PAYMENT_METHOD],PAYER[STATUS],PAYER[PAYER_INFO][EMAIL],PAYER[PAYER_INFO][FIRST_NAME],PAYER[PAYER_INFO][MIDDLE_NAME],PAYER[PAYER_INFO][LAST_NAME],PAYER[PAYER_INFO][PAYER_ID],PAYER[PAYER_INFO][COUNTRY_CODE],PAYER[PAYER_INFO][SHIPPING_ADDRESS][RECIPIENT_NAME],PAYER[PAYER_INFO][SHIPPING_ADDRESS][LINE1],PAYER[PAYER_INFO][SHIPPING_ADDRESS][CITY],PAYER[PAYER_INFO][SHIPPING_ADDRESS][STATE],PAYER[PAYER_INFO][SHIPPING_ADDRESS][POSTAL_CODE],PAYER[PAYER_INFO][SHIPPING_ADDRESS][COUNTRY_CODE],TRANSACTIONS[0][AMOUNT][TOTAL],TRANSACTIONS[0][AMOUNT][CURRENCY],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][ID],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][STATE],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][PAYMENT_MODE],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][PROTECTION_ELIGIBILITY],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][PARENT_PAYMENT],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][AMOUNT][TOTAL],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][AMOUNT][CURRENCY],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][TRANSACTION_FEE][VALUE],TRANSACTIONS[0][RELATED_RESOURCES][0][SALE][TRANSACTION_FEE][CURRENCY]

When i try to output one of them such as:
<cfoutput>#FORM.PAYER[PAYER_INFO][EMAIL]#</cfoutput>

I get this error

Element PAYER is undefined in a Java object of type class [Ljava.lang.String;.

A:

Since your form variable names are like structures you shouldn't access the variables using . notation. When you use the . variable it will consider as 
<cfoutput>#FORM.PAYER[PAYER_INFO][EMAIL]#</cfoutput>

PAYER is a key in Form structure. 
instead you can get the data as below
<cfoutput>#FORM["PAYER[PAYER_INFO][EMAIL]"]#</cfoutput>

In this case coldfusion will treat PAYER[PAYER_INFO][EMAIL]  as a key in Form structure

