csrf token is valid just in first submit using ajax

Another method would be to return the new csrf hash in the response to your AJAX post, then update the value of the csrf token field in your table in the $.ajax success callback. Then you could just change your data to retrieve the value from the field instead of using "<?=$this->security->get_csrf_hash();?>" in the script.

You could also retrieve the URL from the form so you don't have to repeat that information in the script.

Bonfire

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