function is_number(obj){ return Object.prototype.toString.call(obj)==='[object Number]'; }
function is_boolean(obj){ return Object.prototype.toString.call(obj)==='[object Boolean]'; }
function is_string(obj){ return Object.prototype.toString.call(obj)==='[object String]'; }
function is_null(obj){ return Object.prototype.toString.call(obj)==='[object Null]'; }
function is_undefined(obj){ return Object.prototype.toString.call(obj)==='[object Undefined]'; }
function is_object(obj){ return Object.prototype.toString.call(obj)==='[object Object]'; }
function is_array(obj){ return Object.prototype.toString.call(obj)==='[object Array]'; }
function is_function(obj){ return Object.prototype.toString.call(obj)==='[object Function]'; }
function quote(str){ return '"' + str + '"'; }

var basic_map = {
    '[object Undefined]': true,
    '[object Number]': true,
    '[object Null]': true,
    '[object Boolean]': true 
}
function basic_type(obj){ return basic_map[ Object.prototype.toString.call(obj) ]; }

    
JSON = window.JSON || {};
//JSON.stringify
JSON.toStr = function(obj){
    if(is_string(obj) || is_null(obj) || is_number(obj) || is_boolean(obj)) return quote(obj);
    if(is_undefined(obj)) return obj;
    
    if(is_array(obj)){
        var left = "[",
            middle = [],
            right = "]",
            value;
        var callee = arguments.callee;
        for(var i=0,len=obj.length; i<len; i++){
            var value = obj[i];
            if( typeof value === 'undefined' ){
                middle.push(null+'');
            }else{
                if( basic_type(value) ){
                    middle.push( value )
                }else{
                    middle.push( callee(obj[i]) )
                }
            }
        }
        return left+ middle.join(",") +right;
    }
    
    if(is_object(obj)){
        var left = "{",
            middle = [],
            right = "}",
            value ;
        var callee = arguments.callee;
        for(var key in obj){
            var value = obj[key];
            if(typeof obj[key] === 'undefined') continue;
            if( basic_type(value) ){
                middle.push( quote(key) + ':'+ value );
            }else{
                middle.push( quote(key) + ':'+ callee(value) );
            }
        }
        return left + middle.join(', ') + right;
    }
};
!JSON.stringify && (JSON.stringify = JSON.toStr);