Form field validation not working in modal window


I have created a web form using the Hubspot form module. I’ve implemented a modal window for the form to be displayed in after the user clicks the modal window trigger.

The form displays properly and can successfully be submitted. The problem is that none of the form’s required fields are being respected. A user is able to submit a completely empty from, even though all fields are set to “Required”, and successfully lands on the destination page.

Why are required fields not failing form validation if they are left empty?

I’ve put together a test page with a Hubspot form being displayed in a modal window. All fields in the form are marked as required, but as a user I am still able to submit an empty form.

I am using the Featherlight.js to implement the modal functionality:

Here’s the test page preview URL from our Hubspot account: