The alert box dispalys an alert message, when the value of a field is changed or when a form is loaded. It is used in the on change field action or on load form action script.
alert <value>;where,
value - the alert message to be displayed.
Alerts the week of the year of a date field when a date is entered by the user.
form FormA { Date1 ( type = date on change { alert(input.Date1.getWeekOfYear() + "th week of the year"); } ) }