Polymer 1.0 has support for shadow DOM, but also what they call "Shady DOM": https://www.polymer-project.org/1.0/articles/shadydom.html https://www.polymer-proj

Polymer 1.0 has support for shadow DOM, but also what they call "Shady DOM": https://www.polymer-project.org/1.0/articles/shadydom.html https://www.polymer-project.org/1.0/articles/shadydom.html TL;DR: Shady DOM provides an API that is similar to shadow DOM, but without all the crazy overhead when polyfilling it. The downside is that it's not quite transparent to someone outside of a Polymer element