files/en-us/web/api/networkinformation/downlinkmax/index.md
{{APIRef("Network Information API")}}{{SeeCompatTable}} {{AvailableInWorkers}}
The downlinkMax read-only property of the {{domxref("NetworkInformation")}} interface returns the maximum downlink speed, in megabits per second (Mbps), for the underlying connection technology.
A number 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() {
let connectionType = "not supported";
let 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);
{{Specifications}}
{{Compat}}