proxy.pac

function FindProxyForURL(url, host) {
  // Define proxy servers
  var proxyServer1 = "PROXY proxy1.synically-ackward.com:8080";
  var proxyServer2 = "PROXY proxy2.synically-ackward.com:8080";
  
  // Define bypass list for specific URLs
  var bypassList = [
    "*.google.com",
    "facebook.com",
    "*.example.com"
  ];

  // Check if the host is in the bypass list
  for (var i = 0; i < bypassList.length; i++) {
    if (shExpMatch(host, bypassList[i])) {
      return "DIRECT";
    }
  }

  // Measure response time of proxy servers
  var responseTime1 = measureResponseTime(proxyServer1);
  var responseTime2 = measureResponseTime(proxyServer2);

  // Determine the preferred proxy based on response time
  if (responseTime1 < responseTime2) {
    return proxyServer1;
  } else {
    return proxyServer2;
  }
}

function measureResponseTime(proxy) {
  // Perform a network request and measure the response time
  // ...
  return responseTime;
}