Popup opens as new browser window in Edge and Internet Explorer

Problem: Opening a popup with JavaScript in Edge or Internet Explorer results in a new browser window instead of a popup window. For example:

var popup = window.open("https://www.duckduckgo.com/", "DDG", "height=640,width=960,toolbar=no,menubar=no,scrollbars=no,location=no,status=no");

Communication between the new window and originating site is not possible either, since both

popup

window.opener

Solution: This can happen if the originating site’s URL and popup URL are not in the same security zone. Ensure that both are in the Trusted Sites zone in Internet Options!