如何在 Pnotify 中将焦点设置在按钮上

我在我的项目中使用 pnotify Alert jquery。我试图在弹出对话框时将焦点设置在“确定”按钮上。这样用户只需按 Enter 或空格键即可关闭对话框。但无法做到这一点。

这是 pnotify 的链接 http://sciactive.com/pnotify/
我的代码 -

 function AlertAskOk(Heading, Message, type, okclick) {
            var modal_overlay;

            info_box = $.pnotify({
                title: Heading,
                text: Message,
                type: type,
                buttons: 'ok',
                okclick: okclick,

                icon: "picon picon-object-order-raise",
                delay: 20000,
                history: false,
                stack: false,
                // nonblock: true,

                before_open: function (pnotify) {

                    //  $("btn-inverse").focus();
                    // Position this notice in the center of the screen.
                    pnotify.css({
                        "top": ($(window).height() / 2) - (pnotify.height() / 2),
                        "left": ($(window).width() / 2) - (pnotify.width() / 2)
                    });

                    // Make a modal screen overlay.
                    modal_overlay = $("<div />", {
                        "class": "ui-widget-overlay",
                        "css": {
                            "display": "none",
                            "position": "fixed",
                            "top": "0",
                            "width": "5000px",
                            "bottom": "0",
                            "right": "0",
                            "left": "0",
                            "cursor": "pointer"

                        }
                    }).appendTo("body").fadeIn("fast");
                },

                //....

                after_open: function (ui) {
        $(".btn", ui.container).focus();
    },
                //....

                before_close: function () {
                    modal_overlay.fadeOut("fast");
                }
            });

        }

Use after_open callback。检查这个demo http://jsfiddle.net/o5jb5q0a/.

new PNotify({
   //....
    after_open: function (notify) {
        $(".btn-class", notify.container).focus();
    }
   //....
});