Internet Explorer: From the top menu, select "View", then "Internet Options". On the "Security" tab, ensure that "Internet Zone" is selected in the "Zone" pull-down menu. If the "Custom" radio button is checked, then click the settings button, scroll to the bottom and click the "Enable" radio button under "Active Scripting". Click "OK".
Netscape: From the top menu, select "Edit" then "Preferences". In the tree menu on the left, click "Advanced" (not any of the items below it, but "Advanced" itself). Ensure that the checkbox on the right labeled "Enable JavaScript" has a checkmark in it. Then click "OK".