Now it's time to add a login page to our application. The screen itself is very simple, and appears like the following figure:
The two fields Username and Password should have validation. The validation is enabled with the help of the constraint attribute. This attribute can contain a combination of the following options:
a regular expression
In our example, we use no empty.
How to validate a form
In the earlier chapters, we used WrongValueException to validate a single input field. However, when we click on the button and submit the data of form, validation ...