OReilly JavaScript The Good Parts 关于Object.prototype和delete

Every object is linked to a prototype object from which it can inherit properties.

All objects created from object literals are linked to Object.prototype，

an object that comes standard with JavaScript.

When you make a new object, you can select the object that should be its prototype.

We will add a beget method to the Object function. The beget method creates a new object

that uses an old object as its prototype.

if (typeof Object.beget !== 'function'){    Object.beget = function(o)    {        var F = function () {};        F.prototype = o;        return new F();    };}var stooge={               name:"hebian",              "no.":"001"             };  var another_stooge = Object.beget(stooge);document.write(another_stooge.name);

The prototype link has no effect on updating. When we make changes to an object, the object's prototype is
not touched:

another_stooge.name = "joy";document.write(another_stooge.name);document.write(stooge.name);

The prototype relationship is a dynamic relationship. If we add a new property to a prototype, that property
will immediately be visible in all of the objects that are based on that prototype:

stooge.professional = 'actor';document.write(another_stooge.professional);document.write(stooge.professional);

The prototype link is used only in retrieval. If we try to retrieve a property value from an object, and if the
object lacks the property name, then JavaScript attempts to retrieve the property value from the prototype
object. And if that object is lacking the property, then it goes to its prototype, and so on until the process
finally bottoms out with Object.prototype.

The delete operator can be used to remove a property from an object. It will remove a property from the
object if it has one. It will not touch any of the objects in the prototype linkage.

delete another_stooge.name;document.write(another_stooge.name);