今天突然看到了园子里使用的jQuery.json，把源码复制在这里，以后会有用，免得忘了。

(function($) {
    $.toJSON = function(o) 
    {
        if (typeof (JSON) == 'object' && JSON.stringify)
            return JSON.stringify(o);
        var type = typeof (o);
        if (o === null)
            return "null";
        if (type == "undefined")
            return undefined;
        if (type == "number" || type == "boolean")
            return o + "";
        if (type == "string")
            return $.quoteString(o);
        if (type == 'object') 
        {
            if (typeof o.toJSON == "function")
                return $.toJSON(o.toJSON());
            if (o.constructor === Date) 
            {
                var month = o.getUTCMonth() + 1;
                if (month < 10)
                    month = '0' + month;
                var day = o.getUTCDate();
                if (day < 10)
                    day = '0' + day;
                var year = o.getUTCFullYear();
                var hours = o.getUTCHours();
                if (hours < 10)
                    hours = '0' + hours;
                var minutes = o.getUTCMinutes();
                if (minutes < 10)
                    minutes = '0' + minutes;
                var seconds = o.getUTCSeconds();
                if (seconds < 10)
                    seconds = '0' + seconds;
                var milli = o.getUTCMilliseconds();
                if (milli < 100)
                    milli = '0' + milli;
                if (milli < 10)
                    milli = '0' + milli;
                return '"' + year + '-' + month + '-' + day + 'T' + 
                hours + ':' + minutes + ':' + seconds + '.' + milli + 'Z"';
            }
            if (o.constructor === Array) 
            {
                var ret = [];
                for (var i = 0; i < o.length; i++)
                    ret.push($.toJSON(o[i]) || "null");
                return "[" + ret.join(",") + "]";
            }
            var pairs = [];
            for (var k in o) {
                var name;
                var type = typeof k;
                if (type == "number")
                    name = '"' + k + '"';
                else if (type == "string")
                    name = $.quoteString(k);
                else
                    continue;
                if (typeof o[k] == "function")
                    continue;
                var val = $.toJSON(o[k]);
                pairs.push(name + ":" + val);
            }
            return "{" + pairs.join(", ") + "}";
        }
    };
    $.evalJSON = function(src) 
    {
        if (typeof (JSON) == 'object' && JSON.parse)
            return JSON.parse(src);
        return eval("(" + src + ")");
    };
    $.secureEvalJSON = function(src) 
    {
        if (typeof (JSON) == 'object' && JSON.parse)
            return JSON.parse(src);
        var filtered = src;
        filtered = filtered.replace(/\\["\\\/bfnrtu]/g, '@');
        filtered = filtered.replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']');
        filtered = filtered.replace(/(?:^|:|,)(?:\s*\[)+/g, '');
        if (/^[\],:{}\s]*$/.test(filtered))
            return eval("(" + src + ")");
        else
            throw new SyntaxError("Error parsing JSON, source is not valid.");
    };
    $.quoteString = function(string) 
    {
        if (string.match(_escapeable)) 
        {
            return '"' + string.replace(_escapeable, function(a) 
            {
                var c = _meta[a];
                if (typeof c === 'string')
                    return c;
                c = a.charCodeAt();
                return '\\u00' + Math.floor(c / 16).toString(16) + (c % 16).toString(16);
            }) + '"';
        }
        return '"' + string + '"';
    };
    var _escapeable = /["\\\x00-\x1f\x7f-\x9f]/g;
    var _meta = {'\b': '\\b','\t': '\\t','\n': '\\n','\f': '\\f','\r': '\\r','"': '\\"','\\': '\\\\'};
})(jQuery);