Day 1: What is JavaScript & The Console

Daily Objective

Understand where JavaScript runs (browser engines like V8 and Node.js), connect a script to HTML, and execute code using the browser console.

1. Where Does JavaScript Run?

JavaScript is an interpreted, high-level, multi-paradigm programming language. Initially created for web browsers, it now runs on servers via runtime environments like Node.js.

2. Linking a Script to HTML

Always link scripts right before the closing </body> tag or use the defer attribute in the <head>:

<!-- In index.html -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>JS Fundamentals</title>
  </head>
  <body>
    <h1>JavaScript in Action</h1>
    <script src="script.js"></script>
  </body>
</html>

3. The Developer Console

In script.js:

console.log('Hello, JavaScript!');
console.info('Helpful information');
console.warn('This is a warning');
console.error('This is an error message');

Open Chrome DevTools (F12 or Ctrl + Shift + I) and view the Console tab.

Daily Hands-on Practice (70%)

1. Create index.html and script.js in a new folder and open with Live Server.
2. Log mathematical expressions like console.log(25 * 4) and string combinations.
3. Open Node.js in your terminal by typing node and evaluate basic expressions.