JavaScript components--ecmascript, DOM, BOM,

1. JavaScript components

While JavaScript and ECMAScript are often used to express the same meaning, JavaScript has a much larger meaning than what is stated in the ECMA-262 standard. A complete JavaScript should consist of the following three different parts

• Core (ECMAScript);

ECMAScript is a script programming language that is standardized by the ECMA International (formerly the European Association of Computer manufacturers, the English name is European Computer Manufacturers Association) through ECMA-262. ECMAScript defines only the basis of this language, and on top of that it builds a more complete scripting language. Our common web browser is just one of the possible hosting environments for ECMAScript implementations. The components are: syntax, types, statements, keywords, reserved words, operators, objects, and so on.

Currently there are 6 versions of ECMAScript, namely ECMAScript1,ECMAScript2,ECMAScript3,ECMAScript4 (due to the differences in the formulation of too large, not formally cloth),ECMAScript5, ECMAScript2015. As of the release date, the official JavaScript name is ECMAScript 2015, and the next version will be released this year (2016), named ECMAScript 2016. Starting in 2015, the new version will be published in the form of ecmascript+ years.

• Document Object Model (DOM)-corresponds to the Documents object;

An interface that is independent of the programming language of the system platform, through which programs and scripts can dynamically access and modify the content, structure, and style of the document.

The DOM understands a document as a family tree (a node tree) of Parent (parent node), child (subnode), sibling (sibling node), such as:

　　

A document is a collection of nodes with the following types of nodes:

ELEMENT nodes (tags), text nodes (contained in element nodes), attribute nodes (more specific descriptions of elements)-almost all elements have a title property

• Browser object Model (BOM)--corresponding Window object

It provides many objects for accessing the browser's functions, which are not related to any Web content;

Do not introduce more temporarily, and then do the explanation later.

JavaScript components--ecmascript, DOM, BOM,