jquery get elements currently in view

Here are some options using javascript and jquery to get elements currently in view (visible on screen). The appear plugin works very well.

function isScrolledIntoView(elem)
    var docViewTop = $(window).scrollTop();
    var docViewBottom = docViewTop + $(window).height();

    var elemTop = $(elem).offset().top;
    var elemBottom = elemTop + $(elem).height();

    return ((elemBottom >= docViewTop) && (elemTop appear plugin: http://code.google.com/p/jquery-appear/

$('#foo').appear(function() {
  $(this).text('Hello world');

waypoints plugin: http://imakewebthings.github.com/jquery-waypoints/