lockfixed is a jQuery plugin which allows for DOM elements to be positioned anywhere on the page, and lock within the user's viewport when scrolling. Common use case is a menu under a header, which on scrolling stays within the viewport and doesn't overflow the footer.
Degrades nicely on mobile and tablet browsers and doesn't have any CSS prerequisites. Demo
An Angular.js directive which allows you to perform any javascript actions (in the controller, or on the element) when an element is scrolled into or out of, the users viewport, without requiring any other dependencies. Demo
Visualize reading progress with small and simple jQuery plugin. Demo
Highly customizable custom scrollbar jQuery plugin, featuring
vertical/horizontal scrollbars, scrolling momentum, mouse-wheel,
keyboard and touch support etc. Demo
A simple, lightweight jQuery plugin used to display a progress bar
at the top of the page that fills up as the user scrolls. Demo
Overscroll is a jQuery Plugin and polyfill for mobile safari's overflow-scrolling style. It is intended for use on desktop browsers, with the latest version of jQuery. Demo
jQuery plugin for promotional content that appears with user scrolling Demo
Easily reveal elements as they enter the viewport. Demo