Mozilla Firefox (1.0) Select 'Tools' from the top menu Choose 'Options' Choose 'Web Features' from the left navigation Select the checkbox next to 'Enable JavaScript' and click OK ...

Click the Advanced button to open the Advanced JavaScript Options box. Check the boxes under Allow scripts to section that you want to allow. Click OK To enable JavaScript in Firefox (MAC): ...

Learn how to enable a visual tab switcher, much like the OS X Command-Tab application switcher, in the Firefox 3.6 beta releases.

Select Preferences from the Firefox menu. In the pop-up window, click the Content icon. Check the Enable JavaScript check box. Close the window. To enable JavaScript in Safari (MAC): ...