How to load data from db with ajax?
I suppose your list is implemented with views (if not you can easily do this), to load a view via Ajax use the following code; I supposed your view's name is VIEW_NAME and it's display machine name is block_0 and there is a contextual filter to get filter

$.ajax({
    url: Drupal.settings.basePath + 'views/ajax',
    type: 'POST',
    dataType: 'json',
    data: 'view_name=VIEW_NAME&amp;view_display_id=block_0&amp;view_args='+filter,
    success: function(response) {
        var output = response[1].data;
        $("#filter").html(output);
    },
   error: function(data) {
        alert('An error occured!');
    }
});


The Ajax call in Drupal framework is different to the one you usually see on non-Drupal websites.