"JavaScript"--Overview

I. Overview

JavaScript is a kind of programming language with object-oriented ability and interpretive type. That is, it is object-and event-driven and has a relatively secure client-side scripting language. Because he doesn't need to run in a language environment, it only needs to support its browser. Its main purpose is to verify the data sent to the server side, increase the web interaction, enhance the user experience and so on.

Second, the characteristics

1. Explanatory
JavaScript is a scripting language and is a widely used scripting language for client Web development, often used to add dynamic functionality to HTML pages, such as responding to user actions.
2. Object-based language
JavaScript is an object-based programming language, but not a fully object-oriented language, because without the concept of a class, everything is derived from a copy of an existing object.
3. Dynamic Nature
JavaScript is event-driven and can respond directly to user or customer input without having to go through a Web server program. Event-driven is the action that occurs when an action is performed on the home page.
4. Cross-platform
JavaScript relies on the browser itself, regardless of the operating environment, as long as the computer can run the browser, and support JavaScript browser, it can be executed correctly
5. Security
JavaScript, as a security language, is not allowed to access local hard disks, and cannot store data on the server, modify and delete network documents, and only browse or dynamically interact with the browser. So as to effectively prevent the loss of data or illegal access to the system.

iii. structure of knowledge

JavaScript is divided into the following three parts: ECMAScript, BOM, and Dom.

ECMAScript: ECMAScript has no dependencies on the Web browser. 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. It mainly includes syntax, type, statement, keyword, reserved word, operator, object and other components.

BOM (Brower object Model): It provides a number of objects for accessing the functionality of the browser. However, the BOM itself is not standard. BOM core object is window, basic architecture

DOM (document Object Model): an API (Application interface) for HTML and XML documents. The DOM depicts a hierarchical node tree that runs a developer to add, remove, and modify portions of a page. has become a truly cross-platform, language-neutral way of showing and manipulating page markers.

JS is our front-end development necessary knowledge, after the course learning and project implementation, are inseparable from JavaScript, after the study is based on JS, we must carefully grasp the content of the various parts.

"JavaScript"--Overview