Hi Madhavan,

Firstly, you will need to know the payment result (if it's successful or not) and check that value to determine the Enabled property of the Pay button. Its default value would be False, and when the payment is successful, would be turned to True.

I can think of 2 ways to refresh that value:

• You can use JavaScript timeout to Ajax-refresh that button every X seconds. Frankly this is not the best way as it would refresh a part of the screen unnecessarily very frequently
• Or better, you can have a push mechanism which would let a certain page know that there is a change in a status, and you would disable the button by checking that new status. But that would require some new coding and using a library like Firebase.

I would actually suggest that you check the status of the payment right before you proceed with the actual payment operation. So if it is already paid, you would not continue with the operation and show the user a warning message like "Payment already done". 

The Pay button would not be disabled in that case, but it's more important to always check the payment status in backend before proceeding, anyway.