viewport.jquery
Simple but handy jQuery plugin adding methods and CSS selectors
viewport is a simple but handy jQuery plugin that adds methods and CSS selectors to check if the element is in a certain viewport. Furthermore - you will be able to check the position relation of two separate elements even if the are not kin. The plugin uses getBoundingClientRect() to determine element positions so be sure it meets your browser support requirements. ] version 1. x.x uses different detection principles, which will work in almost any browser but work 10-30 times slower.