js object --> jsonStr（javascript 对象转为 json字符串）

//经测试 可用
Object.prototype.deep_clone = function(){  
    eval("var tmp = " + this.toJSON());  
    return tmp;  
}

Object.prototype.toJSON = function(){  
    var json = [];  
    for(var i in this){  
        if(!this.hasOwnProperty(i)) continue;  
        //if(typeof this[i] == "function") continue;  
        json.push(  
            i.toJSON() + " : " +  
            ((this[i] != null) ? this[i].toJSON() : "null")  
        )  
    }  
    return "{\n " + json.join(",\n ") + "\n}";  
}

  
Array.prototype.toJSON = function(){  
    for(var i=0,json=[];i<this.length;i++)  
        json[i] = (this[i] != null) ? this[i].toJSON() : "null";  
    return "["+json.join(", ")+"]"  
}  
  
String.prototype.toJSON = function(){  
    return '"' +  
        this.replace(/(\\|\")/g,"\\$1")  
        .replace(/\n|\r|\t/g,function(){  
            var a = arguments[0];  
            return  (a == '\n') ? '\\n':  
                    (a == '\r') ? '\\r':  
                    (a == '\t') ? '\\t': ""  
        }) +  
        '"'  
}

  
Boolean.prototype.toJSON = function(){return this}  

Function.prototype.toJSON = function(){return this}  

Number.prototype.toJSON = function(){return this}  

RegExp.prototype.toJSON = function(){return this}  
  
// strict but slow  
String.prototype.toJSON = function(){  
    var tmp = this.split("");  
    for(var i=0;i<tmp.length;i++){  
        var c = tmp[i];  
        (c >= ' ') ?  
            (c == '\\') ? (tmp[i] = '\\\\'):  
            (c == '"')  ? (tmp[i] = '\\"' ): 0 :  
        (tmp[i] =   
            (c == '\n') ? '\\n' :  
            (c == '\r') ? '\\r' :  
            (c == '\t') ? '\\t' :  
            (c == '\b') ? '\\b' :  
            (c == '\f') ? '\\f' :  
            (c = c.charCodeAt(),('\\u00' + ((c>15)?1:0)+(c%16)))  
        )  
    }  
    return '"' + tmp.join("") + '"';  
}
//测试：var obj = new object(); obj.id = '007'; var jsonStr = obj.toJSON();