What is the function of the object prototype _ _ proto__ in Javascript

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Description

1. All objects have an attribute _ _ proto__ that points to the prototype prototype object of the constructor. The reason why we can use the properties and methods of the constructor prototype prototype object is that the object has a _ _ proto__ prototype.

2. The meaning of the _ _ proto__ object prototype is to provide a direction or a route for the object search mechanism, but it is a non-standard attribute, so this attribute can not be used in actual development, it only refers to the prototype object prototype.

Example

Function Star (uname, age) {this.uname = uname; this.age = age;} Star.prototype.sing = function () {console.log ('I can sing');} var ldh = new Star ('Andy Lau', 18); var zxy = new Star ('Jacky Cheung', 19); ldh.sing () Console.log (ldh); / / the system itself adds a _ _ proto__ to the prototype object prototype console.log of our constructor (ldh.__proto__ = = Star.prototype) / / search rules for methods: first check whether there is a sing method on the ldh object. If so, execute the sing / / if there is no sing method on this object, because of the existence of _ _ proto__, go to the constructor prototype object prototype to find the sing method. Thank you for your reading. The above is the content of "what is the function of object prototype _ _ proto__ in Javascript". After the study of this article, I believe you have a deeper understanding of what the role of object prototype _ _ proto__ in Javascript is, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!