August 9, 2019

How to Enable JavaScript in Mozilla Firefox

People who are average PC users tend to confuse JavaScript with the programming language. JavaScript is a scripting language. JavaScript is used in websites to manage the page layouts and numerous functions. You should know that once you download firefox, you will have JavaScript turned on by default.

Many websites like to enhance their content by animating menus and playing sounds. JavaScript is the tool to accomplish this task. JavaScript can make our content much more media-powerful. When you notice some errors on your websites like broken images, it can slow down the performance of your Firefox web browser. The problem can be caused by the fact that JavaScript has been disabled. In this article, you will learn how to re-enable it through advanced settings menus.

How to Enable JavaScript in Mozilla Firefox

  1. First of all, you must check which Mozilla Firefox version you have installed on your computer. To do this press “Alt + H” to enable the “Help” menu and press “About Firefox.” In our tutorial we work with Mozilla Firefox 23 and up versions.
  2. Now, you need to open the Firefox browser. The icon of Firefox is well-known for its cute illustration of a fox curled around a blue-colored globe. In case you have Firefox already open, you must click “Ctrl + T” to open a new tabbed window.
  3. Next, you should type “about:config” into the Firefox address bar and click “Enter” to open a configuration menu. Later you can come back to the configuration menu even without typing. The only thing you must do is to add the bookmark “Ctrl + D.”

  1. Note that the settings in the configuration menu should be used by advanced PC users, that is why you should press “Continue” when you see the warning message “I’ll be careful, I promise.” Mozilla Firefox wants to be sure you are familiar with advanced settings, and you know what you do. If you have doubts, think twice before applying these advanced changes.

  1. You must type “javascript.enabled” in the search bar. You can see the list of available settings in the alphabetical order. Every set has a preference name, a status, a type, and a value. When you type the needed term in the search bar, you clear away the entries you do not need right now. You can do your search differently. Press on the desired settings under “Preference Name” and then click the “j” key. You will see displayed all the setting, which starts with the letter “j.”
  2. If the value of “javascript.enabled” is indicated as “false,” you must click it twice to change the value to “true.” Now you will have JavaScript enabled by default.

  1. Do not forget to press the “Refresh” button. By refreshing you activate all the changes, you have just done. The “Refresh” button looks like an arrow curled into a circle (see the right side of your address bar). Alternatively, you can press the “F5” on your keyboard.

Troubleshooting Add-ons

If you followed all our recommendations of “instructions how to enable Javascript in your web browser” to enable JavaScript, and Mozilla Firefox still shows poor performance, you can troubleshoot this issue in several ways.

Press the “Alt + T” in order to open a new tab. The rest of the tabs must be closed. When you refresh Mozilla Firefox, you clear up all settings and add-ons. By doing this, you return the Firefox browser to the default settings. Many users are afraid to open their data. To avoid this, it is essential to close all the tabs and keep the blank tab open.

Now you must press the “Help” menu and choose the “Troubleshooting Information.” Users who don’t see the menu toolbar must click “Alt.”

Press to refresh Mozilla Firefox.

Once this is done, press “Refresh Firefox” once again to confirm your adjustments. It is important to note that when you press to refresh Mozilla Firefox, this action removes all add-ons but you can re-download those back.


All the web browsers come with built-in support for JavaScript. Now you know what to do in case you want to enable/disable this support. As you can see, there is nothing complicated in the procedure. Good luck!

About the author 

Anu Balam

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