isScrolledIntoView.js

function isScrolledIntoView(element) {
    var scrollTop = $(window).scrollTop();
    var scrollBottom = scrollTop + $(window).height();
    var elementTop = $(element).offset().top;
    var elementBottom = elementTop + $(element).height();
    return ((elementBottom >= scrollTop) && (elementTop <= scrollBottom) && (elementBottom <= scrollBottom) && (elementTop >= scrollTop));
}

isScrolledPastBottomOfElement.js

/**
 * Determines if client scrolled past bottom of element
 * 
 * @returns {Boolean}
 */
function isScrolledPastBottomOfElement(selector) {
    var element = $(selector);
    if(element && element.length > 0) {
        var scrollBottom = ($(window).scrollTop() + $(window).height()) - 40;
        var elementBottom = $(element).offset().top + $(element).height();
    }
    return ((scrollBottom >= elementBottom));
}