What kind of language is JavaScript?

Javascript is a lightweight, interpreted or just-in-time compiled programming language with function priority; JavaScript is a dynamic scripting language based on prototype programming, multi-paradigm, and supports object-oriented, imperative and declarative style.

The operating environment of this article: windows7 system, javascript version 1.8.5, Dell G3 computer.

JavaScript ("JS" for short) is a lightweight, interpreted or just-in-time compiled programming language with function priority. Although it is famous as a scripting language for developing Web pages, it is also used in many non-browser environments. JavaScript is a dynamic scripting language based on prototype programming, multi-paradigm, and supports object-oriented, imperative and declarative (such as functional programming) style.

JavaScript was first designed and implemented in 1995 by Brendan Eich of Netscape Company on the Netscape Navigator browser. Because Netscape was working with Sun, Netscape management wanted it to look like Java, hence the name JavaScript. But in fact its grammatical style is closer to Self and Scheme.

The standard for JavaScript is ECMAScript. As of 2012, all browsers fully support ECMAScript 5.1, and older browsers support at least the ECMAScript 3 standard. On June 17, 2015, ECMA International released the sixth edition of ECMAScript, which is officially called ECMAScript 2015, but is often called ECMAScript 6 or ES2015.

JavaScript script language has the following characteristics:

(1) Script language. JavaScript is an interpreted scripting language. Languages ​​such as C and C are compiled first and then executed, while JavaScript is interpreted line by line during the running of the program.

(2) Based on objects. JavaScript is an object-based scripting language that can not only create objects but also use existing objects.

(3)Simple. The JavaScript language uses weakly typed variable types and does not impose strict requirements on the data types used. It is a scripting language based on Java's basic statements and controls, and its design is simple and compact.

(4)Dynamic. JavaScript is an event-driven scripting language that can respond to user input without going through a Web server. When visiting a web page, JavaScript can directly respond to these events when the mouse is clicked, moved up or down, or moved in the window.

(5) Cross-platform. The JavaScript scripting language does not depend on the operating system and only requires browser support. Therefore, after writing a JavaScript script, it can be brought to any machine for use, provided that the browser on the machine supports the JavaScript scripting language. JavaScript has been supported by most browsers. [6] Unlike server-side scripting languages, such as PHP and ASP, JavaScript is mainly used as a client-side scripting language to run on the user's browser and does not require server support. Therefore, in the early days, programmers preferred JavaScript to reduce the burden on the server, but at the same time it also brought about another problem, security.

As servers become more powerful, although programmers prefer scripts running on the server to ensure security, JavaScript is still popular for its cross-platform and easy-to-use advantages. At the same time, some special functions (such as AJAX) must rely on JavaScript to be supported on the client side.

[Recommended learning: js basic tutorial]

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