Brian Cryer's Web Resources


Proxy Auto-Configuration (file). A PAC file (which is a .js file) provides a means to allow browser proxy configuration to be configured through the use of a single JavaScript function FindProxyForURL()

Conceptually each time the browser needs to download an item, it calls FindProxyForURL() to determine how the item can be downloaded. For performance reasons the results from FindProxyForURL are often cached.

The function FindProxyForURL is passed two parameters, the name of the item and the hostname derived from the item URL. The FindProxyForURL function returns a semi-colon separated list of instructions indicating what methods can be used to download the item.


For more information see: