The New Dialog API in HTML5.2

The new dialog API allows web developers to open and close a dialog box that behaves like a modal. It sits on the top level of the browser and, depending on the behavior you need, allows for two different interactions. The first is a modal that doesn't allow the user to interact with any content on the page except the modal. The second allows the user to interact with the modal or the content on the page.

This is a modal. You cannot interact with any content on the page. The rest of the page goes darker gray.

This is a popup. You can interact with any content on the page. The rest of the page does not go darker gray.