Skysa

A Scroll-to-top button for scrolling up to the top of the current page. Customize the label and icon used for the button. When the app button is clicked the page scrolls to the top with a smooth eased animation. The Scroll-to-Top button displays on a Skysa bar at the bottom of your site.
http://www.youtube.com/watch?v=Zj1uGXX2xrk&hd=1 
<a href="https://wordpress.org/extend/plugins/tags/skysa-apps" rel="ugc">More Skysa App plugins</a> -|||- <a href="https://wordpress.org/extend/plugins/skysa-official/" rel="ugc">Skysa App Bar Integration plugin</a>

Skysa Scroll-to-Top App

Animated scroll-to-top, button floats unobtrusively at the bottom of your site. A great convenience feature for your visitors.

Skysa Bar apps are self-contained apps which work with the Skysa bar. If you do not have your own Skysa App Bar integrated with your site, they will pull in a basic one for you so that the apps load correctly. If you do integrate your own Skysa App Bar with your site, your Skysa Bar apps will work with it instead, allowing you to configure all the features that the full Skysa App Bar service provides.
This plugin includes the most recent version of the <code>skysa-required</code> directory which is required for the any Skysa Bar app plugins created with this SDK. Additionally, this plugin includes examples of working Skysa Bar apps which are fully documented to show exactly how to build a Skysa Bar app yourself.
<blockquote>
<h4>Note</h4>
This plugin is intended only for WordPress plugin developers to enable the creation of production WordPress plugins; it is not intended to be run in a production environment itself.
</blockquote>

Skysa App SDK

Software Development Kit for creating standalone Skysa Bar apps for WordPress.

Skysa Scroll-to-Top App vs Skysa App SDK