26. __________ the process of checking that information provided by users : 1321004.
26. __________ is the process of checking that information provided by users conforms to rules to ensure that it appropriately answers a form’s questions and is provided in a format that the site’s back-end programs can work with.?
28. Creating a function to validate required fields generally involves retrieving the values of the required fields and checking if the value of any of them is? __________.
29. For all custom validation, it can be helpful to use the __________ structure? for handling errors.