Have you tried this?
Follow these instructions to activate and enable JavaScript in Firefox.
PC & MAC
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.
I followed your directions, it was already set to true, so I set it false, then set it true and it still doesn’t work.