How can I implement custom validation for form controls?

How can I implement custom validation for form controls?

You can create custom validation by using JavaScript to define your validation rules and applying them to your form controls.

Can you give me an example of how to validate an email field?

Sure! You can use a regular expression to check if the email format is correct. Here's a simple example:

function validateEmail(email) {
    const regex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
    return regex.test(email);
}

What if I want to show an error message when validation fails?

You can display an error message by manipulating the DOM. For example, if the email is invalid, you can set the innerHTML of a span element to show the error.

Is there a way to validate multiple fields at once?

Yes, you can loop through all the form fields and apply your validation logic to each one, collecting any errors to display at once.