how to check if a customer navigate to paypal site. and if he close the browser and do not return back to the main site. then i have to do my code at this point.. if any idea.
and is it possible to pass my text to paypal site to show warning not to close the page etc et
You can use Paypal’s Instant Payment Notification (IPN) functionality to process a payment even if the user closes the browser down before they are redirected back to your site.
It’s not clear from your question tags if you need a php or an asp.net solution, but the article below provides an excellent breakdown on how to integrate PayPal with a .net web-site –
http://www.codeproject.com/Articles/42894/Introduction-to-PayPal-for-C-ASP-NET-developers