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

What is JavaScript?

JavaScriptis 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 installJavaScript extensionsorprivacy extensionsthat 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 trydisabling your extensionsto 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. Typeabout:configin theaddress barand pressEnterReturn.
   A warning page may appear. ClickAccept the Risk and Continueto go to theabout:configpage.
2. Find thejavascript.enabledpreference. It should be set totrueby default.
3. Ifjavascript.enabledis set tofalse,click the Toggleor Resetbutton to set it back totrue.

_{JavaScript is a trademark or registered trademark ofOracle Corporationin the U.S. and other countries.}