Japanese version.

JavaScript is a programming language used to add dynamic functionality to web pages and applications. It is one of the three elements used to create web pages and is a fundamental technology for web development, along with HTML and CSS.

JavaScript was developed in 1995 as a browser-based programming language. It runs in web browsers, allowing for dynamic changes to the content displayed on web pages and enabling interaction with users. By using JavaScript, you can add features like animations, slideshows, and form validation to web pages.

Like other programming languages, JavaScript has its own syntax and structure. For example, you can declare variables, use conditional statements, and perform loop operations. JavaScript is also used on the server-side through platforms like Node.js.

JavaScript is an essential language for web development and is used in many websites and applications. For example, popular sites such as YouTube, Facebook, and Amazon all use JavaScript. It is also an indispensable language for web application development. Furthermore, the OfficeScript language used for automation, like Excel macros, is also based on JavaScript, and an increasing number of web tools require knowledge of JavaScript. Therefore, even if you are not a systems engineer, learning JavaScript is a great weapon.


Development and Testing Using Chrome.

What is a Variable?

Variable Data Type

Primitive types

null (special value indicating that the value does not exist)
undefined (special value indicating a variable has not been assigned a value)
symbol (data type representing unique identifiers)

Object types



Prototype chain


Assignment Operators

Arithmetic Operators

Comparison Operators

Logical Operators

Ternary Operator

Bitwise Operators

Integration with HTML

Basic integration between HTML and JavaScript

DOM(Document Object Model)

Event handling