PAC, or proxy auto-configuration, files automatically configure browser proxy settings when the browser’s proxy “configuration from a file” setting is enabled and pointed at the specific proxy file. A proxy PAC file contains javascript code. At its simplest, a PAC file gives the Web browser a specific proxy to use for all connections that the proxy administrator for all Web browsers on his network by editing the PAC files being used. More complicated PAC files can specify different proxies for different Web addresses when browsers try to access them. You can test the PAC file on your computer before deploying it on the network server.
