How to Enable JavaScript in Firefox

By Aaron Parson

Turn JavaScript on or off in Firefox's about:config page. JavaScript is necessary for many websites to work correctly.

Things You'll Need

  • Computer with Internet access

JavaScript -- not to be confused with the programming language Java -- is a scripting language used in Web development. Many websites use JavaScript to help with page layout or function, so Firefox has JavaScript turned on by default. If the feature gets disabled, however, every version of the browser since 23 has the setting to re-enable JavaScript hidden on the about:config page.

Step 1:

Browse to about:config in any Firefox window. On the warning page, press I’ll Be Careful, I Promise! to enter the configuration page.

Step 2:

Type JavaScript in the search bar on the page to filter the list to the settings that concern JavaScript.


Make sure to use the Search bar atop the about:config page, not the browser search bar used to search the Web.

Step 3:

Find the entry titled javascript.enabled and double-click it to switch the value column to read “true” instead of "false."


The "javascript.enabled" line will appear in bold if JavaScript is disabled. Bolded settings indicate settings changed from their defaults.

Turn on JavaScript.

Step 4:

Refresh any other open tabs or windows to reload the pages with JavaScript enabled.


Some Firefox extensions, most notably NoScript, disable JavaScript on specific sites or across the Web. If the “javascript.enabled” setting is already “true” but JavaScript doesn't work, check your extension settings. In NoScript, open the extension's menu to allow scripts through on the current site or to Allow Scripts Globally.

The NoScript menu has options to allow or block JavaScript.