I am currently creating a website that allows anonymous users to input data (or comments) into a database and allows other anonymous users to the site to vote up or down the comments presented on the site.
I have already created the functionality to allow a user to create a comment and allow another user to vote on the comment. The problem I'm having though is thinking how I can limit each visitor to the site to only vote on each comment once.
My idea was to create a session ID when the user votes and then when they try and vote again to try and compare if a session ID already exists. This would work but only until the session is destroyed. Does anyone have any other ideas of how this could be achieved?
I am assuming I might be able to use some of the $_SERVER options available
Thanks in advance