w3schools
Search W3Schools :  
  
HOME HTML CSS XML JAVASCRIPT ASP PHP SQL MORE...   References Examples Forum About

JavaScript Comments

« Previous Next Chapter »

JavaScript comments can be used to make the code more readable.


JavaScript Comments

Comments can be added to explain the JavaScript, or to make the code more readable.

Single line comments start with //.

The following example uses single line comments to explain the code:

Example

<script type="text/javascript">
// Write a heading
document.write("<h1>This is a heading</h1>");
// Write two paragraphs:
document.write("<p>This is a paragraph.</p>");
document.write("<p>This is another paragraph.</p>");
</script>

Try it yourself »


JavaScript Multi-Line Comments

Multi line comments start with /* and end with */.

The following example uses a multi line comment to explain the code:

Example

<script type="text/javascript">
/*
The code below will write
one heading and two paragraphs
*/
document.write("<h1>This is a heading</h1>");
document.write("<p>This is a paragraph.</p>");
document.write("<p>This is another paragraph.</p>");
</script>

Try it yourself »


Using Comments to Prevent Execution

In the following example the comment is used to prevent the execution of a single code line (can be suitable for debugging):

Example

<script type="text/javascript">
//document.write("<h1>This is a heading</h1>");
document.write("<p>This is a paragraph.</p>");
document.write("<p>This is another paragraph.</p>");
</script>

Try it yourself »

In the following example the comment is used to prevent the execution of a code block (can be suitable for debugging):

Example

<script type="text/javascript">
/*
document.write("<h1>This is a heading</h1>");
document.write("<p>This is a paragraph.</p>");
document.write("<p>This is another paragraph.</p>");
*/
</script>

Try it yourself »


Using Comments at the End of a Line

In the following example the comment is placed at the end of a code line:

Example

<script type="text/javascript">
document.write("Hello"); // Write "Hello"
document.write(" Dolly!"); // Write " Dolly!"
</script>

Try it yourself »

« Previous Next Chapter »


1,050,724 Sites built with Wix. Make your own!

Click here to design a Stunning Flash Website for Free

Wix is a revolutionary web design tool that provides anyone with the possibility to create professional and beautiful websites for free.

With e-commerce features, search engine visibility and many more professional tools, Wix is the ultimate solution for creating a spectacular site while saving tons of money.



FUNC Travel
WEB HOSTING
Best Web Hosting
PHP MySQL Hosting
Top 10 Web Hosting
UK Reseller Hosting
Web Hosting
FREE Web Hosting
Top Web Hosting
Windows Hosting
WEB BUILDING
Download XML editor
FREE Flash Website
FREE Web Templates
Website Monetization
FLIGHT TICKETS
Find the cheapest flight
to any destination now!
EDUCATION
US Web Design Schools
HTML Certification
JavaScript Certification
XML Certification
PHP Certification
ASP Certification
STATISTICS
Browser Statistics
Browser OS
Browser Display
W3Schools.com HOME | TOP | PRINT | FORUM | ABOUT
W3Schools is for training only. We do not warrant the correctness of its content. The risk from using it lies entirely with the user.
While using this site, you agree to have read and accepted our terms of use and privacy policy.
Copyright 1999-2009 by Refsnes Data. All Rights Reserved.