Comments in JavaScript help you explain code and prevent mixing. They guide anyone who reads or edits your script.
Table of Content
Understand Comments in JavaScript
A comment is a note inside code that JavaScript does not run. You can use it to explain steps or hide code for later use.
You can write a short note with // or you can add a long note with /* */. Short notes work for one line, while long notes can cover many lines.
Comments show what the code does, so you can understand it and work on it later. You can use them to tell why you use a step and not only what the step does.
They help both you and others when you read the code after some time. Here is an example:
// This sets a value
let x = 10;
/* This block
shows more than one line
so you can explain more */
let y = 20;The Differences Between Single Comments and Multiple Comments in JavaScript
A single comment uses // to add a note on one line. A multiple comment uses /* */ to add a note that can cover many lines.
Here is a table for key differences:
| Type | Symbol | Length | Use Time |
|---|---|---|---|
| Single Comment | // | One line only | Best for short notes |
| Multiple Comment | /* */ | Many lines | Best for long notes or block |
You use a single comment when you want to explain a line or stop one step in the script.
While the multiple comments when you need to write a long note or stop many lines at once.
Examples
Single comment to explain one line:
// This sets the age value
let age = 25;Multiple comments to explain many lines:
/* These lines set two values
then add them for a total */
let a = 10;
let b = 20;
let sum = a + b;Disable code with comments:
// let price = 50;
// let qty = 4;
// let total = price * qty;Wrapping Up
You can use // for single-line notes and /* */ for multiple-line notes. They do not run as code.
Comments explain steps and stop code temporarily.
FAQs
How to write single-line comments in JavaScript?
// This is a single-line comment in JavaScript
console.log("Hello, world!");How to write multi-line comments in JavaScript?
/*
This comment helps you write a long note when the code needs a detailed description.
*/
console.log("This block needs attention for the hashing.");Why are comments important in JavaScript code?
- It helps you to explain the complex code and logic
- It makes the code more readable for other developers
- It stops the code when you do a test
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