Creating a web-component: VanillaJS vs X-Tag vs Polymer

It seems like these days the most trending concept in the HTML5 world is web components. But what the fuss is all about? In order to make such a simple thing as a container expanding on click in past we needed to write CSS and JavaScript. Today thanks to checkbox-hack and :focus or :target pseudo-selector we go on with CSS-only. In fact by using `summary`/`details` elements we do not need any tricks with CSS to make it working, considering that browser already supports this feature. Thus by placing this elements in the DOM we declare specific functionality, CSS is used for styling and JavaScript if still used only for extending the element basic behavior. That is how it is meant initially. However HTML brings just a few new elements what is hardly enough to replace all the custom plugins, libraries and snippets we use. But what if customs elements could be created by anybody? If source code, styles and markup could be kept encapsulated in a package? If the package could be included into HTML document by a link? It sounds almost like an industrial revolution. Just imagine that you need a slideshow on your page. So you add a link to a corresponding component and simply wrap your image slides with custom `img-slider` element. Thats it, you have a running slideshow. You want something else? Just search in the web-components repository. In the other hand you can switch to a UI library based on web components, e.g. Mozilla Brick and build the entire application with web components Exciting, isnt it?

That is in theory. I never have a grip on a new thing until I try it in practice. So I invite you to learn web components with me in practice.