Most reservation forms, if not all, need a way in which certain dates cannot be selected because they have been chosen by prior form users.
If you have a reservation form for any reason, this widget is invaluable.
The widget allows you to display a calendar on your form which your users can select dates that correspond with the purpose of the form. If prior form users have selected a date or a range of dates, they will be grayed out - they cannot be selected.
For the widget to work properly, you need to get a Jotform API key from your account settings, so that the widget can reference previous selections and prevent a date from being selected twice.