설명 :

Sample object: 

var student = { 

name : "홍길동", 

sex : "남", 

age : 24 };

코드 :

Object.objsize = function(Myobj) {
    var osize = 0, key;
    for (key in Myobj) {
        if (Myobj.hasOwnProperty(key)) osize++;
    }
    return osize;
};

var student = { 
name : "홍길동", 
sex : "남", 
age : 24 };

var objsize = Object.objsize(student);
alert('Size of the current object : '+objsize);

결과 :

Size of the current object : 3