For those interested in further research have a look this Netscape page.

Procedure

1. Trust me. Do you? (:)

2. Cut and paste one of the .pac files from the tools page. Save the file as itsname.pac in the directory of your choice. I use c:\Proxy\viaprox.pac in the example. Insert your own proxys in place of the ones in the script.

3. In Netscape Communicator version 4.0x

• Choose the Edit menu.
  
• Choose Preferences.
  
• Click on the + sign in the box linked to the Advanced menu.
  
• Choose Proxies.
  
• Select the Automatic Proxy Configuration Radio Button.
  
• Type file:///C|/Proxy/viaprox.pac (or wherever you wish) in the text input box. (change the .pac file name to the one you want to use.)
  
• Click OK.
  

Opera version 3.xx

• Choose Preference
  
• Set the proxy field as follow:
  HTTP web-cache.any-proxy.domain:####
  HTTPS web-cache.any-proxy.domain:####
  FTP web-cache.any-proxy.domain:####
  GOPHER web-cache.any-proxy.domain:####
  WAIS web-cache.any-proxy.domain:####
  

• Choose the Options menu.
  
• Choose Network Preferences
  
• Choose Proxies
  
• Select Automatic Proxy Configuration
  
• Set Location (URL) to file:///C|/Proxy/viaprox.pac (or wherever you wish)
  

• Choose the Options menu on your web browser.
  
• Select Preferences.
  
• Select Proxies.
  Set the proxy fields as follow:
  FTP Proxy:web-cache.any-proxy.domain port: ####
  Gopher Proxy:web-cache.any-proxy.domain port: ####
  HTTP Proxy:web-cache.any-proxy.domain port: ####
  Security Proxy:web-cache.any-proxy.domain port: ####
  WAIS Proxy:web-cache.any-proxy.domain port: ####
  No Proxy for:
  SOCKS Host:web-cache.any-proxy.domain port: ####
  

• Choose the Options menu.
  
• Choose Preferences
  
• Choose Proxy Set the proxy fields as follow:
  HTTP web-cache.any-proxy.domain:####
  FTP web-cache.any-proxy.domain:####
  WAIS web-cache.any-proxy.domain:####
  GOPHER web-cache.any-proxy.domain:####
  
• Set Location to web-cache.any-proxy.domain:####
  
• Then select the ADD Button on the Domains Box
  

• Open WebExplorer and go to the Configure menu
  
• Go to the Servers on the menu
  
• Under Proxy Gateway enter http://web-cache.any-proxy.domain:####/
  
• The enable proxy box will tick itself.
  
• Close the config box and it then it all seems to work as expected for OS/2
  

• Locate the file lynx.cfg in your ETC directory, and search for the
  word "proxy". Change the next few lines to read:
  
• http_proxy:http://web-cache.any-proxy.domain:####/
  
• ftp_proxy:http://web-cache.any-proxy.domain:####/
  
• gopher_proxy:http://web-cache.any-proxy.domain:####/
  
• no_proxy:
  
• #news_proxy:
  
• #wais_proxy:http://web-cache.any-proxy.domain:####/