? JavaScript Comments

? Quick Overview

Comments are notes you add to your JavaScript code that are ignored by the JavaScript engine. They help explain logic, document your code, or temporarily disable lines.

? Key Concepts

• Single-line comments start with //.
• Multi-line comments use /* ... */.
• Comments never affect how code runs.
• Useful for debugging or explaining logic.

? Syntax & Theory

• // This is a single-line comment
• let x = 5; // store the initial value
• /* This is a multi-line comment */

✍️ Commenting Guidelines (for these notes)

To make comments stand out in your JavaScript notes, every comment inside a code block is wrapped in a special span:

• <span class="comment">// This is a comment</span>
• let x = 5; <span class="comment">// store the initial value</span>
• <span class="comment">/* multi-line comment here */</span>

The CSS rule .code-block .comment makes these comments appear in a different color and italic style.

? Code Examples

// This is a single-line comment
let x = 5; // This is also a single-line comment

// Calculate the total price
let price = 100;
let quantity = 2;
let total = price * quantity;

/*
This is a multi-line comment.
It can span multiple lines.
Use it for longer explanations.
*/
let y = 10;

/*
Temporarily disable a line by turning it into a comment.
This is helpful while debugging or testing.
*/

// let result = complexCalculation(a, b);
console.log("Testing without calculation");

? Live Output & Explanation

Testing without calculation

? Common Use Cases

• Explaining logic behind complex conditions.
• Describing what a function or algorithm does.
• TODO notes such as // TODO: handle invalid input.
• Temporarily disabling code during testing.