Chuck's Academy

Basic JavaScript

Home / Topic / Basic JavaScript / Introduction to JavaScript

Introduction to JavaScript

JavaScript is one of the most popular and essential programming languages in web development. It was originally created to add interactivity to web pages and, over time, has become one of the key technologies for modern web development. In this chapter, we will explore what JavaScript is, its history, and how it integrates into a website.

What is JavaScript?

JavaScript is an interpreted programming language that runs in the user's browser. Unlike languages like PHP, which run on the server, JavaScript runs on the client side, allowing you to modify the content of a web page without needing to reload it.

Main characteristics of JavaScript:

  • It is a high-level language, which means it is easy to understand and write for humans.
  • JavaScript is dynamic, allowing you to change the values of variables and objects at runtime.
  • JavaScript is multi-paradigm: you can program functionally, object-oriented, or procedurally.
  • It is compatible with all modern browsers, making it a crucial tool for web development.

History and Evolution

JavaScript was created in 1995 by Brendan Eich while working at Netscape. Since then, the language has gone through several iterations and has been standardized through the ECMA (European Computer Manufacturers Association) organization.

The JavaScript standard is known as ECMAScript, and the most recent version at the time of writing this course is ECMAScript 2023.

How to Add JavaScript to a Web Page

There are several ways to add JavaScript to a website. The most common is to include JavaScript code directly within an HTML file. Here's a basic example:

html
"Here we have a simple HTML file that includes JavaScript. The page content is a header with the text Hello World. The JavaScript code is within a script tag, which executes a message in the browser console when the page loads. The message is Hello from JavaScript."

Other Ways to Integrate JavaScript

In addition to including JavaScript directly in the HTML, you can also link to an external JavaScript file. This is the preferred option when the code is extensive or reused on multiple pages:

html
"In this example, the HTML file includes a reference to an external JavaScript file called script.js. This file contains all the JavaScript code, which facilitates code organization and maintenance. This is useful when you have large amounts of code that need to be reused."

And the script.js file could have something like the following:

javascript
"The script.js file contains a simple console message with the text Hello from an external JavaScript file, which is useful for testing that the file has been correctly linked."

Development Tools

To develop and debug JavaScript code, the browser offers various tools that facilitate the developer's work. The most important is the browser console, where you can run JavaScript code in real-time and review error or warning messages.

To open the console in Chrome, for example, you can press Ctrl + Shift + J (on Windows) or Cmd + Option + J (on macOS). This will open the development tools, where you can interact with the code.

In addition to the console, you can use specialized text editors like Visual Studio Code or Sublime Text. These editors offer syntax highlighting, autocomplete, and other useful features to write JavaScript code more efficiently.

javascript
"This example creates a variable named message and assigns it the value of Hello World. Then, the value of the variable is printed in the console using console.log."

Conclusion

JavaScript is a fundamental tool for any front-end developer. Its ability to manipulate web page content in real-time, along with its versatility, makes it an essential language. In this chapter, you have learned what JavaScript is, how it was created, and how you can integrate it into your web pages.

Mark as read and continue
Ask me anything