JavaScript settings and preferences for interactive web pages

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  • Revision id: 42189
  • Created:
  • Creator: scoobidiver
  • Comment: JavaScript removed in Fx23 (bug 851702), simplified, privacy extension section
  • Reviewed: No
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This article describes what JavaScript is, how to turn it on and off, what JavaScript settings are available in Firefox and how to allow and block it on certain domains.

This article describes what JavaScript is and how to allow and block it on certain domains.

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.

Enable and disable JavaScript

In Firefox, you can configure whether JavaScript in web pages is permitted to execute or not. To allow JavaScript in Firefox:

  1. Click the menu button New Fx Menu and choose Options.Preferences.
  2. In the OptionsPreferences window, select the Content panel.
    1. Enable JavaScript: Select this option to permit JavaScripts to execute on your computer.
    2. To change advanced settings, click Advanced….



  3. Close the about:preferences page. Any changes you've made will automatically be saved.

Advanced JavaScript settings

Through the Advanced JavaScript Settings window, you can configure the permissions for JavaScript.

JavaScript - Win2

  • Move or resize existing windows: To prevent JavaScripts from changing the position or size of existing windows, deselect this option.
  • Raise or lower windows: This option allows sites to place windows below or above existing windows.
  • Disable or replace context menus: When you right-click an item, a sub-menu may appear. This menu, called a "context menu," can be disabled through JavaScripts. To prevent them from disabling context menus, deselect this option.

Allow and block JavaScript on certain domains

JavaScript can be used to do things that some users find undesirable. For a better control, you can install privacy extensions such as:

  • NoScript that allows JavaScript and other executable content to run only on trusted domains of your choice
  • Ghostery that allows you to block scripts from companies that you don't trust amongst other things.

Based on information from JavaScript (mozillaZine KB)