The function Dog (name) {
this.name=name; 
} 
Let dogA=new Dog (" Paul "); 

T prototype. Eat=true; 
DogA. Eat;//true, obtain the constructor eat attribute 

T prototype=null;//will be the prototype of the constructor instead of null 
DogA. Eat;//true,,, how instance objects and eat? 

According to truth is not a constructor's prototype gone, turns to be null, how do dogA the instance objects can also obtain the eat=true?