Can you post an example of the code you use? You can check the Web Console (Firefox/Tools > Web Developer) for error messages about blocked and unsafe content. You can check the Network Monitor to see if content is blocked or otherwise fails to load. *https://developer.mozilla.org/Tools/Web_Console *https://developer.mozilla.org/Tools/Network_Monitor You can use "Ctrl+F5" or "Ctrl+Shift+R" to reload the page and bypass the cache to generate a fresh log. ---- Note that Firefox 42+ has a Tracking Protection feature that is enabled by default in Private Browsing mode. When you are in private browsing mode then Firefox can show a shield icon at the left end of the location/address bar that some content is affected. You can disable this feature in "Options/Preferences > Privacy" or via the about:privatebrowsing page that get when you open a New Private Window. *Options/Preferences > Privacy: "Use Tracking Protection in Private Windows" *https://support.mozilla.org/kb/tracking-protection-firefox *https://support.mozilla.org/kb/control-center-site-privacy-and-security-firefox

Thanks for responding. It turns out it was a blocking add-on. I was thrown off because I had deactivated all of them once and it did not solve the problem. But when I did it again, it did. It's possible I forgot one one.