BatteryManager: level property

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The BatteryManager.level property 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

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

JavaScript

js
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

Specification
Battery Status API
# dom-batterymanager-level

Browser compatibility

BCD tables only load in the browser

See also