这个问题分为两部分:

当你不知道模态的确切高度时,你如何将模态垂直地放置在中心? 是否有可能有模态居中,并有溢出:auto在模态体,但只有当模态超过屏幕高度?

我试过用这个:

.modal-dialog {
  height: 80% !important;
  padding-top:10%;
}

.modal-content {
  height: 100% !important;
  overflow:visible;
}

.modal-body {
  height: 80%;
  overflow: auto;
}

当内容远远大于垂直屏幕尺寸时,这给了我所需要的结果,但对于较小的模式内容,这几乎是不可用的。


当前回答

下面是另一个css方法,它的工作原理非常好: http://zerosixthree.se/vertical-align-anything-with-just-3-lines-of-css/

萨斯:

.modal {
    height: 100%;

    .modal-dialog {
        top: 50% !important;
        margin-top:0;
        margin-bottom:0;
    }

    //keep proper transitions on fade in
    &.fade .modal-dialog {
        transform: translateY(-100%) !important;
    }
    &.in .modal-dialog {
        transform: translateY(-50%) !important;
    }
}

其他回答

var modalVerticalCenterClass = ".modal";
function centerModals($element) {
    var $modals;
    if ($element.length) {
        $modals = $element;
    } else {
        $modals = $(modalVerticalCenterClass + ':visible');
    }
    $modals.each( function(i) {
        var $clone = $(this).clone().css('display', 'block').appendTo('body');
        var top = Math.round(($clone.height() - $clone.find('.modal-content').height()) / 2);
        top = top > 0 ? top : 0;
        $clone.remove();
        $(this).find('.modal-content').css("margin-top", top);
    });
}
$(modalVerticalCenterClass).on('show.bs.modal', function(e) {
    centerModals($(this));
});
$(window).on('resize', centerModals);

我已经从bellow link下载了bootstrap3-dialog,并修改了bootstrap-dialog.js中的open函数

https://github.com/nakupanda/bootstrap3-dialog

Code

open: function () {
            !this.isRealized() && this.realize();
            this.updateClosable();
            //Custom To Vertically centering Bootstrap 
            var $mymodal = this.getModal();
            $mymodal = $mymodal.append('<table border="0" cellpadding="0" cellspacing="0" width="100%" height="100%"><tr><td align="center" valign="middle" class="centerModal"></td></tr></table>');
            $mymodal = $mymodal.find(".modal-dialog").appendTo($mymodal.find(".centerModal"));
            //END
            this.getModal().modal('show');
            return this;
        }

Css

.centerModal .modal-header{
    text-align:left;
}
.centerModal .modal-body{
    text-align:left;
} 

非常非常简单的方法来实现这个概念,你会得到模态总是在你的屏幕的模块css为flow: http://jsfiddle.net/jy0zc2jc/1/

你必须通过下面的css将模态类显示为表:

display:table

模态对话框为display:table-cell

见完整的工作例子在给定的小提琴

还有另一种解决方案,它将为窗口上的每个可见模态设置有效的位置。调整大小事件和show.bs.modal:

(function ($) {
    "use strict";
    function centerModal() {
        $(this).css('display', 'block');
        var $dialog  = $(this).find(".modal-dialog"),
            offset       = ($(window).height() - $dialog.height()) / 2,
            bottomMargin = parseInt($dialog.css('marginBottom'), 10);

        // Make sure you don't hide the top part of the modal w/ a negative margin if it's longer than the screen height, and keep the margin equal to the bottom margin of the modal
        if(offset < bottomMargin) offset = bottomMargin;
        $dialog.css("margin-top", offset);
    }

    $(document).on('show.bs.modal', '.modal', centerModal);
    $(window).on("resize", function () {
        $('.modal:visible').each(centerModal);

    });
})(jQuery);

添加这个简单的css也可以。

.modal-dialog {
  height: 100vh !important;
  display: flex;
}

.modal-content {
  margin: auto !important;
  height: fit-content !important;
}