函數 inherits

Inherit the prototype methods from one constructor into another.

Usage:

function ParentClass(a, b) { }
ParentClass.prototype.foo = function(a) { }

function ChildClass(a, b, c) {
  // Call parent constructor
  ParentClass.call(this, a, b);
}
ol.inherits(ChildClass, ParentClass);

var child = new ChildClass('a', 'b', 'see');
child.foo(); // This works.