Windows Internet Explorer
Click Tools and then Internet Options
Select the Security tab, and select the Custom Level button
Scroll down to Scripting of Java applets
Make sure the Enable radio button is checked
Click OK to save your preference

Windows Chrome
Enter about:plugins in the search field.
Scan for Java and check whether Java is enabled
(if the Disable link appears, Java is already enabled)
Click on the Enable link (if available)

Browsers for Windows and Mac OS X
Start Mozilla Firefox browser or restart it if it is already running
At the top of the browser, select the Firefox button
(or Tools menu in Windows XP), then Add-ons
The Add-ons Manager tab will open.
In the Add-ons Manager tab, select Plugins
Click Java (TM) Platform plugin to select it
Click on the Enable button
(if the button says Disable, Java is already enabled)

Launch Safari browser
Click on Safari and select Preferences
Click on the Securitytab
Check (select) Enable Java check box
Close Safari Preferences window