https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/defineGetter
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Object/defineSetter 
https://developer.mozilla.org/en/JavaScript/Reference/Operators/Special/set
https://developer.mozilla.org/en/JavaScript/Reference/Operators/Special/get 
https://developer.mozilla.org/en/Core_JavaScript_1.5_Guide/Working_with_Objects#Using_Object_Initializers 

http://msdn.microsoft.com/ko-kr/magazine/cc163419.aspx#S5 
posted by ned3y2k