Often when inputting data to a Management Screen or a Dynamic Form, it's very helpful to be able to check and validate this data as the user is navigating through the Screen and inputting data. This is by no means a replacement for validating the data when it is received by the Snippet used by a Screen, however it can help the user's understanding of the Screen and save the user's time by avoiding data input errors before they are sent.
To follow a worked example on how to do this, please see the Incorporating Data Input Checks into Management Screens tutorial in our main Learn site, which shows you how to utilize client-side scripts to incorporate data-input checking mechanisms into your Management Screen and thereby improve the interactive experience for the users of your Screen.