Procedure

1. For Firefox versions lower than 23, do the following.
   1. On the browser, go to the Options → Content tab.
   2. Verify that Enable JavaScript is selected.
   3. Click OK.
2. For Firefox version 23 or higher, do the following.
   1. In the address bar, type about:config and press ENTER.
   2. Click I'll be careful, I promise!.
   3. Verify that the Value of Preference Name javascript.enabled is set to true.