JavaScript Advanced Programming Learning Notes Chapter 01 JavaScript cognition

Source: Internet
Author: User

Hello World:

Good morning everyone, the so-called spring, set off. Starting today to learn the third edition of Advanced programming the second time before the lightning-fast trend of a cursory glance, but nothing to remember that has been forgotten almost. Haha, originally I am not Huang Rong, also is not a genius, or that sentence good memory is inferior to the written word. The third edition of this study, advanced programming, is targeted and purposeful. So I will record each chapter of learning and notes are recorded here. It is convenient for all of us. No more nonsense, let's start with the first one today, the implementation of JavaScript. Zhang Xin Xu Big God said non-it (computer professional) front-end practitioners learn JavaScript must be systematic learning, how to learn the system, 1th: to JavaScript has a whole perceptual cognition, so we followed this little red Book to step by step Chapter one chapter slowly chew. Come on

The first chapter is the implementation of javascript:

What is JavaScript?

What are the implementations of JavaScript? What is JavaScript made of?

We are the first to understand the problem!

The tree explains it in detail,

JavaScript is a scripting language designed to interact with Web pages (dynamic type, weak type, flexibility) and as the web grows more and more important, it becomes a real programming language. Especially the advent of H5,node and ES6 makes JavaScript more powerful. There is a eminence of momentum. Mom, the egg is far away.

JavaScript = ECMAscript + DOM + BOM composition;

Then what is ECMAScript? There is a language rule that is prescribed by ecmascript262 and described I am so understanding the rules and descriptions of the language of grammar, type, statement, value, reserved word, operator, object, function, etc... The description of the important constituent parts of the language, in my understanding ECMAScript like a boss, and JS more like a staff to perform the tasks assigned by the boss and fulfill the boss's requirements and realize the boss's idea haha. But ECMAScript is actually an important part of JavaScript. is a scripting language based on the ECMAScript implementation.

What is that? The DOM (Document Object model) Document object models provides methods and interfaces for accessing and manipulating the contents of a document's Web page. Dom is also divided into dom1 level dom2 level DOM3 level

The goal of the DOM1 level is that the structure of the mapping document is primarily two components:

First: Dom core, the DOM core is mainly for the XML document structure provides access to and manipulate the XML document structure of arbitrary departments of methods and interfaces.

Second: The extension of the DOM Core: provides methods for HTML objects.

The DOM2 level has been extended to the dom1 level, mainly adding new interfaces and properties:

1. Dom View: Interface for tracking document changes

2. Dom Event: Provides methods and interfaces for binding events to the DOM tree (DOM node element). Internet and IE have compatibility issues.

3. Dom Style: Provides methods and interfaces for adding CSS styles to DOM elements.

4. DOM traversal and Dom scoping: Provides a related API for traversing the DOM tree and Dom scopes.

In short, the method of manipulating the DOM has changed a lot.

The DOM3 level further expands the DOM to support XML 1.0 specifications.

The current mainstream browser support for Dom is quite similar. Some compatibility issues still remain to be resolved.

What's the BOM again? Browser Object Model

The BOM provides methods and interfaces for accessing and manipulating the contents of a browser's web pages.

The main features are as follows:

1. Monitor the browser's forward and back button,

2. Using navigator.useragent to determine the browser version,

3. Get detailed information about the address bar and source of the Web page through the Location object,

4. Use the Screen object to calculate the resolution of the user's display

5. A new window pops up,

6. Move the browser window port to zoom off the browser function.

Operation of the 7.cookies object,

The operation of the ActiveXObject object for 8.xmlrequesthttp and ie. ...... such as

There was no provision for the relevant standards of the BOM before H5. Until the advent of the H5 BOM was incorporated into the prescribed range. So in fact, the BOM still has a lot of pit point.

These are the implementations and components of JavaScript. Come here today, I believe you have a block letters understanding of JavaScript, then we begin to enter the hall of JavaScript. Refueling GO


JavaScript Advanced Programming Learning Notes Chapter 01 JavaScript cognition

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