Several points that need to be clarified regarding Javacript "prototype" and "prototype attribute"

• Each object has a prototype, but not all objects have the prototype attribute. In fact, this attribute is only available to function objects.
  Var a = function (){};
  Var B = [1, 2, 3];
  A. prototype; // function (){}
  B. prototype; // undefined

• The constructor itself is also an object and has its own prototype, but its prototype is not an object referred to by the prototype attribute. A Function is an object whose constructor is a Function. Therefore, the prototype object of the constructor is actually an object referred to by Function. prototype.
• Summary:The prototype of an object is the prototype attribute value of its constructor.. -- Javascript authoritative guide version 5th