In Google Chrome, its really easy task to install the script to enable the Old facebook chat. Just Click the Following link to install Script. CLICK HERE TO GO TO DOWNLOAD SCRIPT PAGE. In the Script page Click ‘INSTALL’ button which is in the Top Right side of the page.
Now the Install Popup will appear, in that box CLICK ‘INSTALL’ and now the Script is Installed.
Now the Script is Installed. Now Close the Existing Facebook page and Open the Facebook again. You can See your Old Favorite Chat is available. If you cant see the old facebook chat, Clear the cache and open the facebook. Anytime you can remove this script from extension menu of the Google chrome to get the New sidebar chat box.