What does navigator do?

JavaScriptJunior~2 min read

1. What navigator is

navigator is a property of the window object, and it represents the Browser Object Model (BOM) - an interface that lets JavaScript interact with the browser, not the page.

javascript

console.log(window.navigator === navigator); // true

2. Example:

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console.log(navigator.userAgent);
console.log(navigator.language);
console.log(navigator.onLine);

Prints information like:

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"Mozilla/5.0 (Windows NT 10.0; Win64; x64)..."
"en-US"
true

3. Main properties of navigator:

Property	What it does
`navigator.userAgent`	a string describing the browser and OS
`navigator.language`	the user's interface language (`"en-US"`, `"uk-UA"`)
`navigator.languages`	an array of preferred languages
`navigator.platform`	the platform/OS (`"Win32"`, `"MacIntel"`, `"Linux x86_64"`)
`navigator.onLine`	`true` if there is internet access
`navigator.cookieEnabled`	`true` if cookies are enabled in the browser
`navigator.hardwareConcurrency`	the number of logical CPU cores
`navigator.deviceMemory`	the device's RAM size (in GB)
`navigator.vendor`	the browser vendor (e.g. `"Google Inc."`)

4. navigator methods:

Method	Description
`navigator.geolocation.getCurrentPosition()`	get the user's geolocation
`navigator.clipboard.writeText()` / `readText()`	work with the clipboard
`navigator.share()`	trigger the system "Share" dialog (on mobile)
`navigator.vibrate()`	vibrate on mobile devices
`navigator.mediaDevices.getUserMedia()`	access the camera and microphone
`navigator.serviceWorker`	work with Service Workers (PWA, offline mode)
`navigator.permissions.query()`	check whether an API is allowed (e.g. geolocation)

5. Usage examples:

Check the browser:

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if (navigator.userAgent.includes("Chrome")) {
  console.log("User is on Chrome");
}

Check the connection:

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if (!navigator.onLine) {
  alert("No Internet connection!");
}

Get the current coordinates:

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navigator.geolocation.getCurrentPosition(pos => {
  console.log(pos.coords.latitude, pos.coords.longitude);
});

This method asks the user for permission.

Copy text to the clipboard:

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navigator.clipboard.writeText("Hello, world!");

Get the user's language:

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console.log(`Your language: ${navigator.language}`);

6. Structure:

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window
 └── navigator
      ├── userAgent
      ├── language
      ├── geolocation
      ├── clipboard
      ├── mediaDevices
      └── ...

In short:

What it does	Provides information about the browser and device
Where it lives	Inside `window` (`window.navigator`)
What you can learn	browser type, language, OS, online status
What you can do	get geolocation, copy to clipboard, trigger share, use the camera
A typical example	`navigator.userAgent`, `navigator.onLine`, `navigator.geolocation.getCurrentPosition()`

Summary: navigator is an object through which JavaScript can learn the browser's and device's characteristics and interact with system capabilities (geolocation, camera, clipboard, PWA, etc.).

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