NetworkInformation.downlinkMax

The NetworkInformation.downlinkMax read-only property returns the maximum downlink speed, in megabits per second (Mbps), for the underlying connection technology.

var max = NetworkInformation.downlinkMax

• an unrestricted double representing the maximum downlink speed, in megabits per second (Mb/s), for the underlying connection technology.

The following example monitors the connection using the change event and logs changes as they occur.

function logConnectionType() {
  var connectionType = 'not supported';
  var downlinkMax = 'not supported';

  if ('connection' in navigator) {
    connectionType = navigator.connection.effectiveType;

    if ('downlinkMax' in navigator.connection) {
      downlinkMax = navigator.connection.downlinkMax;
    }
  }

  console.log('Current connection type: ' + connectionType +
    ' (downlink max: ' + downlinkMax + ')');
}

logConnectionType();
navigator.connection.addEventListener('change', logConnectionType);