## The reason why you should use prototype instead of closure when constructing

### My answer is #2

1. All method/object under prototype is shared among all instances. Memory free.
2. Prototype is faster than closure when instanciating http://stackoverflow.com/questions/3493252/javascript-prototype-operator-performance-saves-memory-but-is-it-faster/4041582#4041582
3. Closure is good for having private members, but private means not white-test-able.