结合A1rPun的回答和StriplingWarrior的建议，我想到了这个:

$(document).on({
    'show.bs.modal': function () {
        var zIndex = 1040 + (10 * $('.modal:visible').length);
        $(this).css('z-index', zIndex);
        setTimeout(function() {
            $('.modal-backdrop').not('.modal-stack').css('z-index', zIndex - 1).addClass('modal-stack');
        }, 0);
    },
    'hidden.bs.modal': function() {
        if ($('.modal:visible').length > 0) {
            // restore the modal-open class to the body element, so that scrolling works
            // properly after de-stacking a modal.
            setTimeout(function() {
                $(document.body).addClass('modal-open');
            }, 0);
        }
    }
}, '.modal');

工作甚至动态模态添加后，并消除了第二个滚动条的问题。最值得注意的是，我发现这个功能很有用，它将模态中的表单与Bootbox警报的验证反馈集成在一起，因为这些使用动态模态，因此需要将事件绑定到document，而不是.modal，因为这只会将它附加到现有的模态。

小提琴。

更新日期:2019年1月22日，13.41 我通过jhay优化了解决方案，它还支持关闭和打开相同或不同的对话框，例如，从一个细节数据向前或向后跨步到另一个细节数据。

(function ($, window) {
'use strict';

var MultiModal = function (element) {
    this.$element = $(element);
    this.modalIndex = 0;
};

MultiModal.BASE_ZINDEX = 1040;

/* Max index number. When reached just collate the zIndexes */
MultiModal.MAX_INDEX = 5;

MultiModal.prototype.show = function (target) {
    var that = this;
    var $target = $(target);

    // Bootstrap triggers the show event at the beginning of the show function and before
    // the modal backdrop element has been created. The timeout here allows the modal
    // show function to complete, after which the modal backdrop will have been created
    // and appended to the DOM.

    // we only want one backdrop; hide any extras
    setTimeout(function () {
        /* Count the number of triggered modal dialogs */
        that.modalIndex++;

        if (that.modalIndex >= MultiModal.MAX_INDEX) {
            /* Collate the zIndexes of every open modal dialog according to its order */
            that.collateZIndex();
        }

        /* Modify the zIndex */
        $target.css('z-index', MultiModal.BASE_ZINDEX + (that.modalIndex * 20) + 10);

        /* we only want one backdrop; hide any extras */
        if (that.modalIndex > 1) 
            $('.modal-backdrop').not(':first').addClass('hidden');

        that.adjustBackdrop();
    });

};

MultiModal.prototype.hidden = function (target) {
    this.modalIndex--;
    this.adjustBackdrop();

    if ($('.modal.in').length === 1) {

        /* Reset the index to 1 when only one modal dialog is open */
        this.modalIndex = 1;
        $('.modal.in').css('z-index', MultiModal.BASE_ZINDEX + 10);
        var $modalBackdrop = $('.modal-backdrop:first');
        $modalBackdrop.removeClass('hidden');
        $modalBackdrop.css('z-index', MultiModal.BASE_ZINDEX);

    }
};

MultiModal.prototype.adjustBackdrop = function () {        
    $('.modal-backdrop:first').css('z-index', MultiModal.BASE_ZINDEX + (this.modalIndex * 20));
};

MultiModal.prototype.collateZIndex = function () {

    var index = 1;
    var $modals = $('.modal.in').toArray();


    $modals.sort(function(x, y) 
    {
        return (Number(x.style.zIndex) - Number(y.style.zIndex));
    });     

    for (i = 0; i < $modals.length; i++)
    {
        $($modals[i]).css('z-index', MultiModal.BASE_ZINDEX + (index * 20) + 10);
        index++;
    };

    this.modalIndex = index;
    this.adjustBackdrop();

};

function Plugin(method, target) {
    return this.each(function () {
        var $this = $(this);
        var data = $this.data('multi-modal-plugin');

        if (!data)
            $this.data('multi-modal-plugin', (data = new MultiModal(this)));

        if (method)
            data[method](target);
    });
}

$.fn.multiModal = Plugin;
$.fn.multiModal.Constructor = MultiModal;

$(document).on('show.bs.modal', function (e) {
    $(document).multiModal('show', e.target);
});

$(document).on('hidden.bs.modal', function (e) {
    $(document).multiModal('hidden', e.target);
});}(jQuery, window));

A1rPun的答案在一个小的修改后完美地工作(Bootstrap 4.6.0)。我的名声不允许我评论，所以我会在网上回复。

我只是替换了。modal.show的每个。modal:visible。

因此，在打开多个情态动词时修复背景:

$(document).on('show.bs.modal', '.modal', function () {
    var zIndex = 1040 + (10 * $('.modal.show').length);
    $(this).css('z-index', zIndex);
    setTimeout(function() {
        $('.modal-backdrop').not('.modal-stack').css('z-index', zIndex - 1).addClass('modal-stack');
    }, 0);
});

和，修复滚动条:

$(document).on('hidden.bs.modal', '.modal', function () {
    $('.modal.show').length && $(document.body).addClass('modal-open');
});

检查情态动词的计数，并将值添加到背景作为z-index

    var zIndex = 1500 + ($('.modal').length*2) + 1;
    this.popsr.css({'z-index': zIndex});

    this.popsr.on('shown.bs.modal', function () {
        $(this).next('.modal-backdrop').css('z-index', zIndex - 1);
    });

    this.popsr.modal('show');

尝试在bootply上将以下内容添加到JS中

$('#myModal2').on('show.bs.modal', function () {  
$('#myModal').css('z-index', 1030); })

$('#myModal2').on('hidden.bs.modal', function () {  
$('#myModal').css('z-index', 1040); })

解释:

在摆弄了属性之后(使用Chrome的开发工具)，我意识到任何低于1031的z-index值都会把东西放在背景后面。

所以通过使用bootstrap的模态事件句柄，我将z-index设置为1030。如果显示#myModal2，如果隐藏#myModal2，则将z-index设置为1040。

Demo

每次你运行sys。showModal函数增加z-index并将其设置为新的模态。

function system() {

    this.modalIndex = 2000;

    this.showModal = function (selector) {
        this.modalIndex++;

        $(selector).modal({
            backdrop: 'static',
            keyboard: true
        });
        $(selector).modal('show');
        $(selector).css('z-index', this.modalIndex );       
    }

}

var sys = new system();

sys.showModal('#myModal1');
sys.showModal('#myModal2');