JAVASCRIPT

bootstrap 4 modal popup remote url

$('body').on('click', '[data-toggle="modal"]', function(){
        $($(this).data("target")+' .modal-body').load($(this).data("remote"));
    });  

bootstrap 4 start modal in modal

var modal_lv = 0;
$('.modal').on('shown.bs.modal', function (e) {
    $('.modal-backdrop:last').css('zIndex',1051+modal_lv);
    $(e.currentTarget).css('zIndex',1052+modal_lv);
    modal_lv++
});

$('.modal').on('hidden.bs.modal', function (e) {
    modal_lv--
});