This article describes what JavaScript® is and how to allow or block it on certain websites.

What is JavaScript?

JavaScript is a standard programming language that can be included in web pages to provide functionality such as menus, sounds, and other interactive features. By default, Firefox enables the use of JavaScript and requires no additional installation.

Allow and block JavaScript on certain domains

JavaScript can be used to do things that some people don't like. For better control, you can find and install JavaScript extensions or privacy extensions that let you disable JavaScript, such as these add-ons:

• NoScript: allows JavaScript and other content to run only on websites of your choice.
• Ghostery: allows you to block scripts from companies that you don't trust.

Websites ask you to enable JavaScript

Websites may tell you that JavaScript is required or ask you to make sure that JavaScript is enabled, even though you don't want JavaScript to be blocked. Turn off any settings to disable JavaScript in your installed extensions or try disabling your extensions to see if you can find the problem. You should contact the developer or visit the website for the add-on, to get help with a specific extension.

For advanced users

1. Type about:config in the address bar and press EnterReturn.
   A warning page may appear. Click Accept the Risk and Continue to go to the about:config page.
2. Find the javascript.enabled preference. It should be set to true by default.
3. If javascript.enabled is set to false, click the Toggle or Reset button to set it back to true.

_{JavaScript is a trademark or registered trademark of Oracle Corporation in the U.S. and other countries.}