The first chapter of JavaScript

Learning the first chapter of JavaScript, JS has a preliminary understanding.

First, JavaScript consists primarily of three parts: the core (ECMAScript), the Document Object Model (DOM), the browser object model (BOM)

ECMAScript is primarily used to provide the core language, which includes syntax, types, statements, keywords, reserved words, operators, and objects. A host environment such as a Web browser is required to provide a basic ECMAScript implementation, while the hosting environment can also provide language.

DOM is an application programming interface for XML that has been extended for HTML, which can map an entire page into a multi-tiered node structure. With DOM, one can easily delete, add, replace, or modify any node. Dom grading, Level 1 primarily maps the structure of the document, while Level 2 adds Dom views, events, styles, traversal, and scope based on level 1.

The BOM mainly deals with browser windows and frames, and provides methods and interfaces for interacting with the browser.

The first chapter of JavaScript