Просмотр поста

<?php

$page = empty($_GET['page']) ? 0 : (int)$_GET['page'];
$url = 'http://'. $_SERVER['HTTP_HOST'] . $_SERVER['SCRIPT_NAME'];

for ($i = $page; $i < ($page + 50);) {
    echo 'Строка №'. ++$i .'<br/>';
}

?>

<div id="loadingbar"><b><i>Загрузка ...</i></b></div>
<input type="hidden" value="50" id="loaded_max" />

#loadingbar {
    background-color: #4a4e34;
    text-align: center;
    position: fixed;
    display: none;
    color: #FFF;
    top: 0;
    right: 0;
    left: 0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.0/jquery.min.js"></script>
<script>
    $(function(){
        $('#loaded_max').val(50);
    });
    
    var url = '<?= $url ?>';
    var loading = false;
    $(window).scroll(function(){
        if ((($(window).scrollTop()+$(window).height())+250)>=$(document).height()) {
            if (loading == false) {
                loading = true;
                $('#loadingbar').css('display', 'block');
                
                var loaded_max = $('#loaded_max').val();
                url = url + '?page=' + loaded_max;
                
                $.get(url, function(loaded){
                    $('body').append(loaded);
                    $('#loaded_max').val(parseInt(loaded_max) + 50);
                    $('#loadingbar').css('display', 'none');
                    loading = false;
                });
            }
        }
    });
</script>