jQuery方法扩展：type, toJSON, evalJSON

(function($) {     // the code of this function is from      // http://lucassmith.name/pub/typeof.html     $.type = function(o) {         var _toS = Object.prototype.toString;         var _types = {             'undefined': 'undefined',             'number': 'number',             'boolean': 'boolean',             'string': 'string',             '[object Function]': 'function',             '[object RegExp]': 'regexp',             '[object Array]': 'array',             '[object Date]': 'date',             '[object Error]': 'error'         };         return _types[typeof o] || _types[_toS.call(o)] || (o ? 'object' : 'null');     };     // the code of these two functions is from mootools     // http://mootools.net     var $specialChars = { '\b': '\\b', '\t': '\\t', '\n': '\\n', '\f': '\\f', '\r': '\\r', '"': '\\"', '\\': '\\\\' };     var $replaceChars = function(chr) {         return $specialChars[chr] || '\\u00' + Math.floor(chr.charCodeAt() / 16).toString(16) + (chr.charCodeAt() % 16).toString(16);     };     $.toJSON = function(o) {         var s = [];         switch ($.type(o)) {             case 'undefined':                 return 'undefined';                 break;             case 'null':                 return 'null';                 break;             case 'number':             case 'boolean':             case 'date':             case 'function':                 return o.toString();                 break;             case 'string':                 return '"' + o.replace(/[\x00-\x1f\\"]/g, $replaceChars) + '"';                 break;             case 'array':                 for (var i = 0, l = o.length; i < l; i++) {                     s.push($.toJSON(o[i]));                 }                 return '[' + s.join(',') + ']';                 break;             case 'error':             case 'object':                 for (var p in o) {                     s.push(p + ':' + $.toJSON(o[p]));                 }                 return '{' + s.join(',') + '}';                 break;             default:                 return '';                 break;         }     };     $.evalJSON = function(s) {         if ($.type(s) != 'string' || !s.length) return null;         return eval('(' + s + ')');     }; })(jQuery);