Credit card debiting and preventing the user from aborting

Hello all I am implementing an online credit card debiting system. To do this, I am using the exceptional CURL (http://curl.haxx.se) with PHP4' exec command to speak to a payment server and to receive return values from the payment server. I am using the German company EOPS AG (http://www.eops.de) for the payment gateway. This works really very well with: # Run our friend CURL exec("/usr/local/bin/curl -m 120 -d \"$eopsDataIn\" https://paygate.jmc.net/cgi-bin/px/ssl_payment.pl -L",$eopsDataOut); where $eopsDataIn contains the parameters the payment server requires and $eopsDataOut is an array, containing the return values. This array is used to check whether the card was debited or not. All this works. However, the process of debiting a card takes around 20 seconds and our previous attempts at online payment have proven that 50% of our customers press STOP, BACK or RELOAD during this 20-second period. This leads to problems as sometimes the transaction is carried out, but no message is displayed, hence the customer presses BUY again and then pays for his or her product twice. (We have had cases where exactly this has happened four times in a row. As our software costs USD 1000.00 per licence, I am sure you can imagine how annoyed this customer was when he got 4x USD 1000.00 on his credit card bill.) My questions is, (how) is it possible to continue executing my debiting script and display the results in the customer's browser even if he or she presses STOP? Or perhaps put another way: When someone presses STOP during the executing of the script, how is it possible to pop up an alert dialog saying something like "Debiting card, pls wait." All I want to do is to prevent the user from intervening during the execution of the debiting script. I am sure that other people who have implemented online ordering systems have come across these problems. I would love to hear from you guys. Thanks a lot! Stefen ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com