Load a Shadow DOM polyfill. The following is a list of elements you canattach a shadow root to: 1. Internally it has has the 5 fundamental Node pointers, parentNode, firstChild, lastChild, nextSibling and previousSibling. dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/shadow/index.html, download the GitHub extension for Visual Studio. Any autonomous custom element with a valid name 2. There are some that can't have a shadow DOM for security reasons (for example ), and more besides. Polyfill details. When the shadow DOM renderer needs to render the visual tree, these internal pointers are updated as needed.