Then we select the “Validate” tab to see the validation options: The default is that the field will not get validated.
For numeric fields, there is a convenient way to validate a value range, but we want to select to run a custom validation script.
Adobe provided a lot of infrastructure to do that with just a simple script.
Let’s take a look at how to do that with a text field that is only supposed to have a value of either ‘AAAA’ or ‘BBBB’ (yes, I know that this does not make much sense in a real PDF form).
Important Validating user input is also important for security.
When you restrict the values that users can enter in forms, you reduce the chance that someone can enter a value that can compromise the security of your site.
You might also have certain restrictions on the values.
Even if users correctly enter an integer, for example, you might need to make sure that the value falls within a certain range.If you imagine form as a dialog between your website and your user, the messages play an important role.Don’t leave it to the auto-generated default messages.In many cases, the values you need are some other data types, like integers or dates.Therefore, you also have to make sure that the values that users enter can be correctly converted to the appropriate data types.If you skip the messages parameter, the plugin will display default, auto-generated messages.