scroll

Check if page scroll is at bottom

May seem odd to check if the page scroll is at bottom, but can be useful if you need to hide something or show something else, as in a back to top button for example.

$('#back-to-top').hide();
$(window).scroll(function(){
    if ( document.body.scrollHeight - $(this).scrollTop()  <= $(this).height() ){
        $('#back-to-top').show();
    } else {
        $('#back-to-top').hide();
    }
});