jQuery.extend({
    ImpromptuDefaults: { prefix: 'jqi', buttons: { '确定': true }, loaded: function() { }, submit: function() { return true; }, callback: function() { }, opacity: 0.6, zIndex: 999, overlayspeed: 'slow', promptspeed: 'fast', show: 'show', focus: 0, useiframe: false },
    SetImpromptuDefaults: function(o) {
        jQuery.ImpromptuDefaults = jQuery.extend({}, jQuery.ImpromptuDefaults, o);
    },
    prompt: function(m, o) {
        o = jQuery.extend({}, jQuery.ImpromptuDefaults, o);
        var ie6 = (jQuery.browser.msie && jQuery.browser.version < 7);
        var b = jQuery(document.body);
        var w = jQuery(window);
        var msgbox = '<div class="' + o.prefix + 'box" id="' + o.prefix + 'box">';
        if (o.useiframe && ((jQuery.browser.msie && jQuery('object, applet').length > 0) || ie6))//if you want to use the iframe uncomment these 3 lines
            msgbox += '<iframe src="javascript:;" class="' + o.prefix + 'fade" id="' + o.prefix + 'fade"></iframe>';
        else {
            if (ie6) jQuery('select').css('visibility', 'hidden');
            msgbox += '<div class="' + o.prefix + 'fade" id="' + o.prefix + 'fade"></div>';
        }
        msgbox += '<div class="' + o.prefix + '" id="' + o.prefix + '"><div class="' + o.prefix + 'container"><div class="' + o.prefix + 'close">×</div><div class="' + o.prefix + 'message">' + m + '</div><div class="' + o.prefix + 'buttons" id="' + o.prefix + 'buttons">';
        jQuery.each(o.buttons, function(k, v) { msgbox += '<button name="' + o.prefix + 'button' + k + '" id="' + o.prefix + 'button' + k + '" value="' + v + '">' + k + '</button>' });
        msgbox += '</div></div></div></div>';

        var jqib = b.append(msgbox).children('#' + o.prefix + 'box');
        var jqi = jqib.children('#' + o.prefix);
        var jqif = jqib.children('#' + o.prefix + 'fade');

        var getWindowScrollOffset = function() {
            return (document.documentElement.scrollTop || document.body.scrollTop) + 'px';
        };

        var getWindowSize = function() {
            var size = {
                width: window.innerWidth || (window.document.documentElement.clientWidth || window.document.body.clientWidth),
                height: window.innerHeight || (window.document.documentElement.clientHeight || window.document.body.clientHeight)
            };
            return size;
        };

        var ie6scroll = function() {
            jqib.css({ top: getWindowScrollOffset() });
        };

        var flashPrompt = function() {
            var i = 0;
            jqib.addClass(o.prefix + 'warning');
            var intervalid = setInterval(function() {
                jqib.toggleClass(o.prefix + 'warning');
                if (i++ > 1) {
                    clearInterval(intervalid);
                    jqib.removeClass(o.prefix + 'warning');
                }
            }, 100);
        };

        var escapeKeyClosePrompt = function(e) {
            var kC = (window.event) ? event.keyCode : e.keyCode; // MSIE or Firefox?
            var Esc = (window.event) ? 27 : e.DOM_VK_ESCAPE; // MSIE : Firefox
            if (kC == Esc) removePrompt();
        };

        var positionPrompt = function() {
            var wsize = getWindowSize();
            jqib.css({ position: (ie6) ? "absolute" : "fixed", height: wsize.height, width: "100%", top: (ie6) ? getWindowScrollOffset() : 0, left: 0, right: 0, bottom: 0 });
            jqif.css({ position: "absolute", height: wsize.height, width: "100%", top: 0, left: 0, right: 0, bottom: 0 });
            jqi.css({ position: "absolute", top: "100px", left: "50%", marginLeft: ((((jqi.css("paddingLeft").split("px")[0] * 1) + jqi.width()) / 2) * -1) });
        };

        var stylePrompt = function() {
            jqif.css({ zIndex: o.zIndex, display: "none", opacity: o.opacity });
            jqi.css({ zIndex: o.zIndex + 1, display: "none" });
        }

        var removePrompt = function(callCallback, clicked, msg) {
            jqi.remove();
            if (ie6) b.unbind('scroll', ie6scroll); //ie6, remove the scroll event
            w.unbind('resize', positionPrompt);
            jqif.fadeOut(o.overlayspeed, function() {
                jqif.unbind('click', flashPrompt);
                jqif.remove();
                if (callCallback) o.callback(clicked, msg);
                jqib.unbind('keypress', escapeKeyClosePrompt);
                jqib.remove();
                if (ie6 && !o.useiframe) jQuery('select').css('visibility', 'visible');
            });
        }
        positionPrompt();
        stylePrompt();

        //Events
        jQuery('#' + o.prefix + 'buttons').children('button').click(function() {
            var msg = jqi.children('.' + o.prefix + 'container').children('.' + o.prefix + 'message');
            var clicked = o.buttons[jQuery(this).text()];
            if (o.submit(clicked, msg))
                removePrompt(true, clicked, msg);
        });
        if (ie6) w.scroll(ie6scroll); //ie6, add a scroll event to fix position:fixed
        jqif.click(flashPrompt);
        w.resize(positionPrompt);
        jqib.keypress(escapeKeyClosePrompt);
        jqi.find('.' + o.prefix + 'close').click(removePrompt);

        //Show it
        jqif.fadeIn(o.overlayspeed);
        jqi[o.show](o.promptspeed, o.loaded);
        jqi.find('#' + o.prefix + 'buttons button:eq(' + o.focus + ')').focus(); //focus the default button
        return jqib;
    }
});