Programming Fundamentals/Introduction Examples JavaScript

Overview

JavaScript, often abbreviated as JS, is a high-level, interpreted programming language. Alongside HTML and CSS, JavaScript is one of the three core technologies of the World Wide Web. JavaScript enables interactive web pages and therefore is an essential part of web applications. The vast majority of websites use it, and all major web browsers have a dedicated JavaScript engine to execute it.^[1]

JavaScript is one of the most popular current programming languages^[2], and is the primary programming language for front-end web development. JavaScript files have a .js file extension. JavaScript has been implemented in multiple platforms with different I/O commands. Several examples follow.

Example

Hello World – Console Log

 // This script displays "Hello world!".
 //
 // References:
 // https://www.digitalocean.com/community/tutorials/how-to-write-your-first-javascript-program
 
 console.log("Hello world!")

Output

Hello world!

Discussion

Each code element represents:

// begins a comment
console.log() writes to the JavaScript console output log
"Hello world!" is the literal string to be displayed

Hello World – Window Alert

 // This script displays "Hello world!".
 //
 // References:
 // https://www.digitalocean.com/community/tutorials/how-to-write-your-first-javascript-program
 
 alert("Hello world!")

Output

Hello world!

Discussion

Each code element represents:

// begins a comment
alert() calls the window alert function to display a message
"Hello world!" is the literal string to be displayed

Hello World – Document Write

 // This script displays "Hello world!".
 //
 // References:
 // https://www.w3schools.com/jsref/met_doc_write.asp
 document.write("Hello world!")

Output

Hello world!

Discussion

Each code element represents:

// begins a comment
document.write() writes output to the current document
"Hello world!" is the literal string to be displayed

JavaScript IDEs

There are many free cloud-based and local IDEs available to begin coding in JavaScript. Check with your instructor or do your own research for recommendations.

Cloud-Based IDEs

Local IDEs

References

Wikiversity: Computer Programming

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[1] Wikipedia: JavaScript

[2] TIOBE: Index

[1]

[2]