How to set custom error messages for your HTML forms

The podcast focuses on adding validation to a form using JavaScript, building upon a previous tutorial where the form's structure was created. The speaker explains how to implement client-side validation, emphasizing its importance for user experience and reducing server requests. They cover disabling native browser validation, accessing form fields with JavaScript, and using the browser's built-in validity API. The tutorial includes adding custom error messages, styling them, and implementing accessibility features for screen readers. The speaker also addresses handling validation for radio buttons and checking field validity as users interact with the form, including focusing on the first invalid element upon submission.