Can you show a screenshot of the message or give an example of a website where that is happening?

Some sites will set a link address to "javascript:void(0)" when they are attaching a script to the link. What happens when you click the link -- nothing? It's possible that the script is blocked or broken. Note: if the link is trying to open in a new tab, that usually won't work: the script attached to the link needs to run within the same page.

If a site is generally known to work in Firefox, these are standard suggestions to try when it stops working normally:

Double-check content blockers: Firefox's Tracking Protection feature, and extensions that counter ads and tracking, may break websites that embed third party content (meaning, from a secondary server).

(A) The shield icon toward the left end of the address bar usually turns a bit purplish when content is blocked. Click the icon to learn more or make an exception. See: Enhanced Tracking Protection in Firefox for desktop.

(B) Extensions such as Adblock Plus, Blur, Disconnect, DuckDuckGo Privacy Essentials, Ghostery, NoScript, Privacy Badger, uBlock Origin or uMatrix usually provide a toolbar button to manage blocked content in a page. There may or may not be a number on the icon indicating the number of blocked items; you sometimes need to click the button to see what's going on and test whether you need to make an exception for this site.

Cache and Cookies: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache (only select Cached web content, don't clear all cookies and site data)

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, click the lock icon at the left end of the address bar. After a moment, a "Clear Cookies and Site Data" button should appear at the bottom. Go ahead and click that. Firefox will ask you to confirm; go ahead and confirm.

Then try reloading the page. Does that help?

Testing in Firefox's Troubleshoot Mode: In this mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is running:

You can restart Firefox in Troubleshoot Mode using either:

• "3-bar" menu button > Help > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled)
• (menu bar) Help menu > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled)

and OK the restart. A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button).

If Firefox is not running:

Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.) A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button).

Note: Don't use the Refresh without first reviewing this article to understand what will be deleted: Refresh Firefox - reset add-ons and settings.

Any improvement?

I had this issue as well. Firefox's troubleshoot mode helped identify the extension 'Bitdefender anti-tracker' as the culprit. Does this mean I cannot use that extension at all - or need to turn it off to use the problem web site? Or is there an alternative extension I could use? Any advice much appreciated!

I had this issue as well. Firefox's troubleshoot mode helped identify the extension 'Bitdefender anti-tracker' as the culprit. Does this mean I cannot use that extension at all - or need to turn it off to use the problem web site? Or is there an alternative extension I could use? Any advice much appreciated!

Bitdefender has an article with these suggestions:

Step 2 – Determine the culprit Anti-tracker category & Add exceptions Click the Bitdefender Anti-tracker extension on the browser toolbar, then click on each category from the list and select Disable blocking for this category:

• Advertising
• Site Analytics
• Customer Interaction
• Social Media
• Essential

If the page works fine after disabling all these five categories, re-enable just one at a time in order to identify the culprit. If the issue persists after disabling these trackers categories, re-enable all of them. Then click the cogwheel from the Bitdefender Anti-tracker extension and Add the current website to the list of Exceptions

Source: https://www.bitdefender.com/consumer/support/answer/28500/

Thank you for your response.

I tried the instructions above which made no difference ie - the website still did not load. Testing in safe mode again confirmed that BitDefender is causing the problem.

I tried clearing the cache and all cookies, and it now seems to work.

Fingers crossed, that it stays working.