I have this website where people can up vote or down vote certain businesses. The voting system uses PHP, MySQL, Javascript and AJAX to function. When a vote is made, the user's IP is put into a database and remembered so they cannot vote again. However, it is possible to use an auto clicker program and set it to click faster than the server can process the voting request, which results in this: http://mcserve.rs/qSmn
I already tried using Javascript to hide/disable the button when clicked until the AJAX request finishes, but that is still too slow.
How can I fix this, or is it fixable at all?
Thanks
EDIT: I know that someone using an auto clicker is a very small percentage but doing so could exploit the entire purpose of the website - I am looking for a way to prevent this from happening.
It shouldn't be taking you that long to process a voting request and you can just block off POST requests from the same client to the upvote URL directly on the server. A much better option would be just to use a login system, but, that must not be an option...
If you specify a key constraint of the IP field in the database table that stores the vote information, you don't need to worry about auto clickers, since for each IP there is at most one row in the table.