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');
});

如果你想要一个特定的模态出现在另一个开放模态的顶部，试着在另一个模态div之后添加最上面的模态的HTML。

这招对我很管用:

<div id="modal-under" class="modal fade" ... />

<!--
This modal-upper should appear on top of #modal-under when both are open.
Place its HTML after #modal-under. -->
<div id="modal-upper" class="modal fade" ... />

终于解决了。我对它进行了多种测试，效果很好。

以下是所有遇到同样问题的人的解决方案: 修改Modal.prototype.show函数(在bootstrap.js或modal.js中)

来自:

if (transition) {
   that.$element[0].offsetWidth // force reflow
}   

that.$element
   .addClass('in')
   .attr('aria-hidden', false)

that.enforceFocus()

TO:

if (transition) {
    that.$element[0].offsetWidth // force reflow
}

that.$backdrop
   .css("z-index", (1030 + (10 * $(".modal.fade.in").length)))

that.$element
   .css("z-index", (1040 + (10 * $(".modal.fade.in").length)))
   .addClass('in')
   .attr('aria-hidden', false)

that.enforceFocus()

这是我发现的最好的方法:检查打开了多少个模态，并将模态和背景的z-index更改为更高的值。

Bootstrap 4.5的简单解决方案

.modal.fade {
  background: rgba(0, 0, 0, 0.5);
}

.modal-backdrop.fade {
  opacity: 0;
}

看看这个!这个解决方案解决了我的问题，几个简单的CSS行:

.modal:nth-of-type(even) {
z-index: 1042 !important;
}
.modal-backdrop.in:nth-of-type(even) {
    z-index: 1041 !important;
}

这是我找到它的地方的链接:Bootply 只要确保需要出现在顶部的.modual在HTML代码中处于第二，这样CSS就可以发现它是“偶数”。