What is javascript and what are its characteristics

JavaScript is a lightweight, interpreted or just-in-time compiled programming language with function priority. It has been widely used in web application development and is often used to add some dynamic effects and interactive functions to web pages; Its characteristics are: 1. Interpreted scripting language; 2. Object-based; 3. Weak type; 4. Dynamic; 5. Cross-platform.

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

What is javascript?

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 based on prototype programming, a multi-paradigm dynamic scripting language, and supports object-oriented, imperative, declarative, and functional programming paradigm.

JavaScript is currently the most popular and widely used client-side scripting language. It is used to add some dynamic effects and interactive functions to web pages, and plays an important role in the field of web development.

JavaScript, HTML and CSS together constitute the web pages we see, among which:

• HTML is used to define the content of the web page, such as title, text, images, etc. ;

• CSS is used to control the appearance of the webpage, such as color, font, background, etc.;

• JavaScript is used to update the content of the webpage in real time , such as obtaining data from the server and updating it to the web page, modifying the style of some tags or the content thereof, etc., to make the web page more vivid.

Characteristics of JavaScript

##1) Interpreted scripting language

JavaScript is an interpreted scripting language. Unlike C, C and other languages ​​that need to be compiled before running, code written in JavaScript does not need to be compiled and can be run directly.

2) Object-based

JavaScript is an object-based scripting language that can not only create objects, but also use existing objects.

3) Weak typing

JavaScript is a weakly typed programming language that does not have strict requirements on the data type used. For example, you can initialize a variable as Any type, you can also change the type of this variable at any time.

4) Dynamic

JavaScript is an event-driven scripting language that can respond to user input without the help of a Web server, such as When we visit a web page, click on the web page with the mouse or scroll the window, JavaScript can directly respond to these events.

5) Cross-platform

JavaScript does not depend on the operating system and can run in the browser. Therefore, after a JavaScript script is written, it can be run on any system, as long as the browser on the system supports JavaScript.

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.

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