Polymer is a new type of library for the web, designed to leverage the existing browser infrastructure to provide the encapsulation and extendability currently only available in JS libraries, to let you create custom HTML elements. From
<select>, elements are the building blocks of HTML. Build anything from a button to a complete application as an encapsulated, reusable element that works across desktop and mobile.
Polymer is based on a set of future technologies, including Shadow DOM, Custom Elements and Model Driven Views. Currently these technologies are implemented as polyfills or shims, but as browsers adopt these features natively, the platform code that drives Polymer evacipates, leaving only the value-adds.
Polymer provides a comprehensive set of elements—both UI and non-UI—that you can use right out of the box. You can mix and match Polymer elements with other elements, including built-in elements and other custom elements.Polymer