X-Tag was just added as an official Mozilla repo on Github - it's a small, JS-only polyfill that enables the Custom Element portion of the W3 Web Components spec (https://dvcs.w3.org/hg/webcomponents/raw-file/tip/explainer/...) and other convenient mechanisms to generate awesome components. X-Tag has broad support coverage for a huge percentage of browsers in active used today on both mobile and desktop - Firefox 5+ desktop/mobile, Chrome 4+ desktop/mobile, Safari 4+ desktop/mobile, IE10 desktop, Opera 12 desktop, and all Android 2.0+ stock browsers.