To enable JavaScript in Microsoft Internet Explorer 5 or Later (for Windows)
1.Open Internet Explorer.
2. On the Tools menu, click Internet Options.
3. On the Security tab, click Internet.
4. Click Custom Level.
5. Scroll down to Active scripting.
6. Click Enable (or Prompt).
7. Click OK.
8. Click Yes.
9. Click OK
In order to disable or enable Javascript on Firefox
1.You need to go into the options/preferences screen. This is done either by selecting "Tools" then "Options" from the main menu.
2.The exact menu location varies depending on your operating system for some reason... This will get you to the options/preferences window.
3.The "Main" section is selected by default so click the "Content" button.
4.Simply tick/untick the "Enable Javascript" checkbox, depending whether you want to disable or enable Javascript and then click the "OK" button.
5.After disabling Javascript any Javascript events or functions on the current page will no longer work.
6.You do not need to reload the page.