JavaScript authoritative Guide (6)-Objects

JavaScript objects can inherit properties from an object called a prototype, and this " Archetypal inheritance " (Prototypal inheritance) is a core feature of JavaScript. In addition to strings, numbers, true, false, NULL, and undefined, the values in JavaScript are objects. Object is mutable, you can add or delete properties of the object, manipulating the object by reference , not by value.

The common use of objects is the Create object and set (set), find (query), delete (delete), detect (Test), enum (Enumerate) object properties.

An attribute with the same name cannot exist in an object, the property value can be any JavaScript value, or (ECMASCRIPT5) can be a getter or setter function (or both). In addition, each property has some associated values, called attribute characteristics , such as writable (writable), Enumerable (enumerable), configurable (configurable ).

In addition to containing attributes, each object also has three related object attributes:

object's prototype (prototype): points to another object whose properties inherit from its prototype object.
Object class: IsA string that identifies the object type.
Extended markup for object (Extensible Flag): Indicates whether a new property can be added to the object (in ECMAScript5).

Three types of JavaScript objects and two types of properties:

built-in objects (native object): An object or class defined by the ECMAScript specification. such as arrays, functions, dates, and regular expressions.
Host Object (Host object): defined by the host environment embedded by the JavaScript interpreter (for example, Web browser). such as HtmlElement. The host object can also be used as a built-in object.
Custom Objects (User-defined object): An object created by the running Javascrip code.
own Property (Own property): An attribute that is defined directly in an object.
Inheritance Properties (Inherited property): An attribute defined in the object's prototype object.

JavaScript authoritative Guide (6)-Objects