Block show the default VtigerCRM Confirmation box to let them decide something.
You could configure the text, the User see.
This configuration result into this in Frontend:

Enter your comment. Wiki syntax is allowed:
   __ __ ______  _   __  ____    ___ 
  / //_//_  __/ | | / / / __ \  / _ \
 / ,<    / /    | |/ / / /_/ / / , _/
/_/|_|  /_/     |___/  \___\_\/_/|_|