HTML style to add to the alert message box (reprint)

The JS:

(function($) {

    $.alerts = {
        alert: function(title, message, callback) {
            if( title == null ) title = 'Alert';
            $.alerts._show(title, message, null, 'alert', function(result) {
                if( callback ) callback(result);
            });
        },

        confirm: function(title, message, callback) {
            if( title == null ) title = 'Confirm';
            $.alerts._show(title, message, null, 'confirm', function(result) {
                if( callback ) callback(result);
            });
        },


        _show: function(title, msg, value, type, callback) {

            var _html = "";

            _html += '<div id="mb_box"></div><div id="mb_con"><span id="mb_tit">' + title + '</span>';
            _html += '<div id="mb_msg">' + msg + '</div><div id="mb_btnbox">';
            if (type == "alert") {
                _html +=