Page animation: Animate HTML Web page elements

This package can be used to animate elements of HTML Web pages.

It can manage one or more animations that may run in parallel.

Each animation is composed of a sequence of steps that apply individual effects to Web page elements.

Currently it supports the effects:

- Show or hide page elements
- Fade in or fade out page elements,
- Replace, append, or prepend HTML content into a page element,
- Slide in and out page elements horizontally or vertically,
- Give emphasis to an page element by drawing a circle around it or underlining it,
- Scroll the page to make a given element visible in the window viewport
- Show a number increasing or decreasing gradually until it reaches a target value

It also supports pseudo-effects for synchronization purposes like cancel a parallel animation, wait a given period of time, or callback a function to execute custom code before or after any animation effect.