Almost every large SPA or project involves date and time input. There are limited options, however, if you also prefer to keep your projects lean and consequently stay away from heavy frameworks such as jQuery, or even Bootstrap.
Appalled at the fact that I have to load 300kb of jquery and jquery UI or hook up bootstrap just to use a calendar, I created this [date][time]picker that's powerful, easy to use, and looks good out of the box.
IE9+, iOS Safari 6+, MS Edge, Chrome 8+, Firefox 6+
Install & Use
Demos and documentation: https://chmln.github.io/flatpickr
flatpickr out in the wild: