A PAC file that picks a random proxy from a list

random_proxy.pac

/*
By Daan Rijks (daanrijks@gmail.com).

Idea & Inititative: Niels Meijer (niels.meijer@leerling.ig.nl)

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License
(http://creativecommons.org/licenses/by-nc-sa/4.0/)
*/

var hosts = ""; // HTTP proxies go here, in the format host:port separated by a single space.

function FindProxyForURL(url, host)
{
    var hostsArray = hosts.split(" ");
    var randomIndex = Math.floor((Math.random() * hostsArray.length));
    return "PROXY " + hostsArray[randomIndex] + "; DIRECT"; // DIRECT makes the browser use no proxy if the chosen proxy doesn't work
}