1. Constraint Validation API

   API for better control over form field validation. Includes support for `checkValidity()`, `setCustomValidity()`, `reportValidity()` and validation states.

2. Form validation

   Method of setting required fields and field types without requiring JavaScript. This includes preventing forms from being submitted when appropriate, the `checkValidity()` method as well as support for the `:invalid`, `:valid`, and `:required` CSS pseudo-classes.

3. Email, telephone & URL input types

   Text input fields intended for email addresses, telephone numbers or URLs. Particularly useful in combination with [form validation](https://caniuse.com/#feat=form-validation)