BatteryManager: level property

Secure context

The level read-only property of the BatteryManager interface indicates the current battery charge level as a value between 0.0 and 1.0. A value of 0.0 means the battery is empty and the system is about to be suspended. A value of 1.0 means the battery is full or the user agent is unable to report the battery status information. When its value changes, the levelchange event is fired.

Value

A number.

Examples

Getting the battery level

HTML

<button id="get-level">Get battery level</button>
<div id="output"></div>

JavaScript

const getLevel = document.querySelector("#get-level");
const output = document.querySelector("#output");

getLevel.addEventListener("click", async () => {
  if (!navigator.getBattery) {
    output.textContent = "Battery manager is unsupported";
  } else {
    const manager = await navigator.getBattery();
    const level = manager.level;
    output.textContent = `Battery level: ${level}`;
  }
});

Result

Specifications

Browser compatibility

See also

• BatteryManager
• getBattery()