isOnScreen by moagrius

An ultra-light jQuery plugin that tells you if an element is in the viewport but with a twist. Maintained by zeusdeux on GitHub, where it has earned 646 stars from the community.

A jQuery plugin for entering and validating Tunisian users' data or any other data. It is made very easy to use and easier to customize. Maintained by Dainerx on GitHub, where it has earned 29 stars from the community.

viewport.jquery - simple but handy jQuery plugin adding methods and CSS selectors to check if element is in certain viewport. Maintained by xobotyi on GitHub, where it has earned 149 stars from the community.