document.addEventListener("DOMContentLoaded", function(event) {
    var cl = document.getElementById('#all_otz');
    cl.onclick = function(ev) {
        var post = {};
        post['num_otz'] = 20;
        post['ajax'] = 'y';
        node = BX('video_feed_block');
        if (!!node) {
            BX.ajax.post(
                'https://www.brtclinic.ru/index.php',
                post,
                function (data) {
                    var el = data.getElementById('video_feed_block');
                    node.innerHTML = el.innerHTML();
                }
            );

        }
    }
});