A refreshing JavaScript Datepicker — lightweight, no dependencies, modular CSS.
Also, take a look to the bottom right of this page to see an example with position automatically adjusted.
Since version 1.0 Pikaday is a stable and battle tested date-picker. Feel free to use it however you like but please report any bugs or feature requests to the GitHub issue tracker, thanks!
Hinderling Volkart AG | BSD & MIT license | Copyright © 2014 David Bushell | BSD & MIT license | Example by MoOx