Javascript Comments

In any programming language, a comment is a statement or a piece of code that is ignored by the browser/compiler. Comments can be used to explain the functionality of a particular code, or to increase its readability.

In Javascript, comments can be added in the following ways:

• // - A Single line comment
• /* */ - A Multi line comment

Including Single Line Comments

Single line comments can be added using //.

Let's have a look at an example:

//This is a single line comment

//A variable 'x' is declared below
var x;

Including Multi Line Comments

Multi line comments can be added using /* */. Let's check an example:

/*This is
 a multi line comment
*/

/*
A variable declaration
*/
var y;

Preventing Code Execution

Javascript comments can also be used to prevent the code from execution, and it can be for testing purposes. Adding a // in before a line changes it from executable code to a comment.

Example:

//Commenting both the lines
//var x = 34 + 5;
//document.write(x);