PerformanceResourceTiming.nextHopProtocol

The nextHopProtocol read-only property is a string representing the network protocol used to fetch the resource, as identified by the ALPN Protocol ID (RFC7301).

When a proxy is used, if a tunnel connection is established, this property returns the ALPN Protocol ID of the tunneled protocol. Otherwise, this property returns the ALPN Protocol ID of the first hop to the proxy.

resource.nextHopProtocol;

A string representing the network protocol used to fetch the resource, as identified by the ALPN Protocol ID (RFC7301).

The following example uses the nextHopProtocol property.

function print_PerformanceEntries() {
  // Use getEntriesByType() to just get the "resource" events
  var p = performance.getEntriesByType("resource");
  for (var i=0; i < p.length; i++) {
    print_nextHopProtocol(p[i]);
  }
}
function print_nextHopProtocol(perfEntry) {
  var value = "nextHopProtocol" in perfEntry;
  if (value)
    console.log("nextHopProtocol = " + perfEntry.nextHopProtocol);
  else
    console.log("nextHopProtocol = NOT supported");
}