gistfile1.txt

$(window).scroll(function(f) {
    var scrolled = $(window).scrollTop();
    $(".artist").each(function() {
        if (isElementInViewport($(this))) {
            if ($(this).attr("data-id") === "23") {} else {
                if ($(this).attr("data-loaded") !== "1") {
                    var e = $(this).attr("data-src");
                    $(this).attr("data-loaded", 1);
                    $(this).find("iframe").attr("src", e);
                }
            }
        } else {
            if ($(this).attr("data-loaded") === "1") {
                var g = $(this).attr("data-id");
                if (g === "1" || g === "2") {} else {
                    $(this).find("iframe").attr("src", "");
                    $(this).attr("data-loaded", 0);
                }
            }
        }
    });
    $(".thing").each(function() {
        var g = $(this).attr("data-id");
        if (isElementInViewport($(this))) {
            if ($(this).attr("data-type") === "art") {
                var e = $(".artmenu[data-id=" + g + "]");
            } else {
                var e = $(".txtmenu[data-id=" + g + "]");
            }            
            $(e).show();
        }
    });

    //distance from top to unload artwork1 and artwork2.
    if (scrolled > 5000) {
        unload($("#artwork1"));
        unload($("#artwork2"));
    }
});


function unload(e) {
    var d = b(e).find("iframe");
    b(d).attr("src", "");
    b(e).attr("data-loaded", 0)
}

function isElementInViewport (el) {
    // Special bonus for those using jQuery
    if (typeof jQuery === "function" && el instanceof jQuery) {
        el = el[0];
    }

    var rect = el.getBoundingClientRect();

    return (
        rect.top >= 0 &&
        rect.left >= 0 &&
        rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && /* or $(window).height() */
        rect.right <= (window.innerWidth || document.documentElement.clientWidth) /* or $(window).width() */
    );
}