When define a class I want to define a class level property, which is shared by all instance objects, how should I defined it?   

I can think of 2 approach:

* Define on constructor

After define constructor function, define property on constructor itself,  

format to access:  

**constructor\_name.propName**
* Define on prototype

After define constructor function, define property on constructor's prototype,  

this might be hidden by instance property,  

format to access:  

**obj.propName**

So, which approach is proper? Or there are other solutions?

**Edit:**
I want to know the case When property is string/number, not a function.