confirm ( message )
confirm ( message , default)

This function displays a message box with “Yes” and “No” buttons. A true value will be returned when the user selects “Yes” and false will be returned when “No” is selected. You may set the default button by setting a second argument to true or false.

ans = confirm("Do you wish to continue")
if ans then
   print "continue on"
else
   print "end everything"
   end
end if

draws

0.9.9.42 - added statement