In certain situations, such as when conducting surveys or accepting competition entries, for example, we may wish to limit the number of submissions that a form user may make. Webform offers some methods for preventing folk from putting through multiple submissions, but it must be said that these methods cannot be guaranteed to be bullet-proof for anonymous users.
Under the heading Submission limit on the Form settings page, we specify that our users are limited to making only one submission by entering Limit to
submission(s) ever. In this way we can prevent users of our Speaker Registration form from submitting more than one entry.
In the case of registered and logged-in site users, Webform ...