Form validation ? When to trigger error validation?

1. At which point should input validation occur in an application?
2. What are the consequences if a form is not validated?
3. How do you validate a form field before submitting?

At which point should input validation occur in an application?

In general, it is best to perform input validation on both the client side and server side. Client-side input validation can help reduce server load and can prevent malicious users from submitting invalid data.

What are the consequences if a form is not validated?

When software does not validate input properly, an attacker is able to craft the input in a form that is not expected by the rest of the application. This will lead to parts of the system receiving unintended input, which may result in altered control flow, arbitrary control of a resource, or arbitrary code execution.

How do you validate a form field before submitting?

What is form validation. Before submitting data to the server, you should check the data in the web browser to ensure that the submitted data is in the correct format. To provide quick feedback, you can use JavaScript to validate data. This is called client-side validation.