How to add comment in javascript?

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Adding comments in JavaScript is essential for improving code readability and providing explanations for complex logic. Comments are non-executable lines of text that are ignored by the JavaScript interpreter. They allow developers to annotate their code, making it easier to understand for themselves and others who may work on the codebase. In this article, we will explore different ways to add comments in JavaScript and discuss best practices for using them effectively.

Single-line Comments

The most common way to add comments in JavaScript is by using single-line comments. Single-line comments start with two forward slashes (//) and continue until the end of the line. Here’s an example:

// This is a single-line comment

Single-line comments are useful for adding short explanations or clarifications to specific lines of code.

Multi-line Comments

In addition to single-line comments, JavaScript also supports multi-line comments. Multi-line comments are enclosed between /* and */ and can span across multiple lines. Here’s an example:

This is a multi-line comment.
It can span across multiple lines.

Multi-line comments are helpful when you need to provide more detailed explanations or comment out a block of code temporarily.

Commenting Best Practices

While adding comments can be beneficial, it’s important to follow some best practices to ensure their effectiveness:

1. Be Concise: Keep your comments short and to the point. Long comments can be overwhelming and may distract from the code itself.

2. Use Proper Grammar and Spelling: Ensure that your comments are grammatically correct and free of spelling errors. This helps maintain professionalism and readability.

3. Explain the Why, Not the What: Instead of explaining what the code does (which should be evident from the code itself), focus on explaining why the code is written in a particular way. This provides valuable insights for other developers.

4. Update Comments Regularly: Code evolves over time, and comments can become outdated. Make sure to review and update your comments whenever you make significant changes to the code.


Adding comments in JavaScript is a crucial practice for maintaining code readability and facilitating collaboration among developers. Single-line and multi-line comments offer different ways to annotate code, depending on the level of detail required. By following best practices, such as being concise and explaining the rationale behind the code, comments can greatly enhance the understanding and maintainability of JavaScript codebases.