Quick and easy flood protection?

Question

I have a site where a user submits a message using AJAX to a file called like.php. In this file the users message is submitted to a database and it then sends a

Answer 1

Another way to do this is to write a hidden form input to the page (that calls like.php) using jQuery. A bot won't be using javascript so your hidden form field won't exist.

Check for the hidden field (assign it a value and a name) and if it exists, then hit the database with the request.

Another way; code a hidden element into the page (). A bot will auto-fill every field in the form, so you just check if this field is populated - a user can't see it so you know it's a bot if you've got content there.

Set the style (display:none;) using jQuery tho... again, a bot won't see the jQuery, so it will think this is a legit form input.

You may want to specify a 'this page requires javascript to run' notice somewhere for the user. Some alternative suggestions. After all - you said 'simple' ;)