Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

I can't get javascript enabled using the normal process on Firefox 40.0.2. How can I do this?

  • 8 replies
  • 53 have this problem
  • 1 view
  • Last reply by fdorow

more options

I loaded firefox 40.0.2 and I can't get Javascript enabled. I've gone into the java screen menu and javascript is enabled, but all of my applications that are running javascript doesn't see it as being enabled. Javascript is working on IE, but I'd prefer to continue using Firefox.

I loaded firefox 40.0.2 and I can't get Javascript enabled. I've gone into the java screen menu and javascript is enabled, but all of my applications that are running javascript doesn't see it as being enabled. Javascript is working on IE, but I'd prefer to continue using Firefox.

Chosen solution

You can check the network.protocol-handler.external.javascript pref on the about:config page to make sure that it is set to default (false).

You can use the search bar on the about:config page to filter for javascript. If other javascript prefs show user set (bold) then you can reset them as well.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

Read this answer in context 👍 5

All Replies (8)

more options

Is it occured in your smart phone...????.

more options

No. It's on my desktop

more options

Javascript is enabled by default, and there is no GUI to disable it. What makes you believe it is disabled in the first place?

I've gone into the java screen menu

What is the 'java screen menu'? Note, Java is something completely different than Javascript. For more information - Google is your friend.

all of my applications that are running javascript

What applications?

more options

Thanks for the thoughts.

Attached is a screenshot of the error message I'm receiving when an application is trying to access javascript. This doesn't come up when running the application in IE.

Also, below are the instructions to enable javascript in Firefox if it isn't enabled (which be default it is enabled). On my system, it says it's enabled, but something is blocking my programs to be able to run it.


1) Open a new Firefox browser window or tab.
 2) Copy the following then paste it into the Firefox address bar: about:config
 3) Hit the Enter key.
 4) On the following page, click the button: "I'll be careful, I promise!"
 5) Find the javascript.enabled row under the Preference Name heading.
 6) Double-click anywhere within the javascript.enabled row to toggle the value from "False" to "True".
 7)  Finally, refresh your browser.
more options

Chosen Solution

You can check the network.protocol-handler.external.javascript pref on the about:config page to make sure that it is set to default (false).

You can use the search bar on the about:config page to filter for javascript. If other javascript prefs show user set (bold) then you can reset them as well.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

more options

It was the network.protocol-handler.external.javascript pref that was set to True. I toggled it to set it to false, reloaded Firefox and things seem to work.

Thank you very much.

more options

You're welcome.

Do you have any idea how this pref got changed?

more options

I'm not sure how it might have gotten changed. The only appl that I've loaded since I re-imaged my laptop has been the Shrew soft VPN.