For Netscape
Navigator, enable Java and JavaScript from the Preferences
option in the Edit menu:

Then select
the Advanced category in Preferences, and be sure that
both Enable Java and Enable JavaScript are checked.

For Internet
Explorer, enable Java and JavaScript from the Internet
Options option of the Tools menu:

Then select
the Security tab of the Internet Options palette:

Then set the
security to the default, (Medium), by pressing the Default
Level if it is not dimmed out. If it is dimmed, then you are
already at the default security level, and your Java and JavaScript
are enabled.