Tests if scroll position is at an elements bottom (uses jQuery)

isAtElementBottom.js

function isAtContainerBottom(el) {
	var
		$window = $(window),
		$el = $(el),
		viewTop = $window.scrollTop(),
		viewBottom = (viewTop + $window.height()),
		containerBottom = Math.floor( $el.offset().top + $el.height() ),
		// amount of pre-bottom space to take into account
		scrollBuffer = 150;

	if ( (containerBottom - scrollBuffer) <= viewBottom ) {
		return true;
	} else {
		return false;
	}
}