a hidden field can be filled by those robots easily (it's just another input type).

Use public key encryption, and encrypt the timestamp. If you can't decrypt the timestamp or its missing, you know a robot is trying to circumvent your throttling attempts, so you throttle it :)

In reply to Re^3: enabling "Submit" button after X seconds. by Anonymous Monk
in thread enabling "Submit" button after X seconds. by mrc

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