The newest version of FireFox does not include a built-in way to disable or enable JavaScript. However, there is a way to work around this.
 In your new FireFox window, type about:config into the address bar and press ↵ Enter.
 Like the prompt says, disabling certain options in this page could disable your warranty or open up your browser and computer to malicious attacks. Try to stick to the task of enabling JavaScript.
 In the search bar in the upper portion of the window, search for javascript.enabled. You will see two results appear.


Be sure you are searching in the right search bar. Type the query into the larger search bar, rather than the smaller one. The correct search bar will be the second one from the top of the window.
 Right click on the javascript.enabled result and click Toggle. The value on the right should change from "false" to "true."


Alternatively, you can just double click javascript.enabled to disable/enable JavaScript.
 Click the red X in the upper-right corner of the screen to exit the window and apply your changes. JavaScript should now be enabled and sites will function properly.
 If you are security-conscious and would like to enable or disable JavaScript from running on certain sites, you will have to download FireFox Addons. Some recommendations are: No-Scriptand QuickJava .
Open a new FireFox window.
Type about:config into the address bar.
Click "I'll be careful, I promise.",
Search for javascript.enabled.
Enable JavaScript.
Exit the window.
Restrict certain sites.
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