$('body').on('click', '.delete-field-item', function(){

    $(this).parent('.form-group').remove();

});


$('.add_field').click(function(){
    var block = $('.fields_video_result');
    var sub_block = '<div class="form-group">'+
        '<input type="text"   class="form-control" value="" name="Fields[video]['+ start_i++ +'][value]">'+
        '<span data-id="none" title="удалить" class="glyphicon glyphicon-trash delete-field-item"></span>'+
        '<div>';
    block.append(sub_block);

});