To activate JavaScript on Internet Explorer for Windows
In the menu "Tools", select "Internet options". 
Click on the "Security" menu. 
Select "Internet". 
Click on "Custom level". 
Scroll down to the section named "Scripting". 
Under "Active Scripting", select "Enable". 
Answer "Yes" to the confirm box that pops up. 
Click "OK" . 
Click "OK" again. 
... And press F5 to refresh the page. 

To activate JavaScript on Firefox
From the browser menu bar, select "Tools", and then "Options". 
Click "Web features" to open the submenu. 
Click the checkbox next to "Enable Javascript". 
Click "OK". 
... And press F5 to refresh the page. 
 
To activate JavaScript on Safari
From the browser menu bar, select "Safari", and then "Preferences". 
Click on "Security". 
Click the "Enable Javascript" box in the "Web Content" section. 
Come back to the original page. 
... And press F5 to refresh the page. 

To activate JavaScript on Mozilla
From the browser menu bar, select "Edit", select "Preferences...". 
In the "Category" list, click on "Advanced". 
Select "Scripts & Plugins" (or « Scripts & Windows in Mozilla 1.0). 
Click the checkbox next to "Navigator" under "Enable Javascript for". 
Click OK. 
... And press F5 to refresh the page. 
 
To activate JavaScript on Netscape
From the browser menu bar, select "Edit", and then "Preferences". 
Select "Advanced" to open a submenu. 
Select "Scripts & Plugins". 
Click the "Navigator" checkbox under "Enable JavaScript for". 
Click "OK". 
... And press F5 to refresh the page. 
 
To activate JavaScript on Opera
From the browser menu bar, select "File", and then "Quick Preferences". 
Click the "Enable Javascript" box. 
... And press F5 to refresh the page.