The Navigator Object

The window.navigator property exposed by browsers points to a Navigator object which is a container object that makes a lot of Web Platform APIs available to us.

The standard and widely implemented properties include:

• cookieEnabled true if cookies are enabled
• geolocation points to the Geolocation object used by the Geolocation API
• language returns a string representing the language currently active in the browser
• onLine returns true if the browser is online (the browsers interpret this in different ways, be aware)
• serviceWorker the ServiceWorkerContainer object assigned to the document (see Service Workers)
• userAgent the name of the User Agent identifier of the browser

The standard methods include:

• registerProtocolHandler() a way to let websites register as handlers for protocols.

There are many more methods and properties which are provided by APIs that are either experimental or implemented as drafts and not yet finalized, or just available on a tiny fraction of browsers, so I haven’t included them here but you can explore them all on MDN.

More browser tutorials:

• Some useful tricks available in HTML5
• How I made a CMS-based website work offline
• The Complete Guide to Progressive Web Apps
• The Fetch API
• The Push API Guide
• The Channel Messaging API
• Service Workers Tutorial
• The Cache API Guide
• The Notification API Guide
• Dive into IndexedDB
• The Selectors API: querySelector and querySelectorAll
• Efficiently load JavaScript with defer and async
• The Document Object Model (DOM)
• The Web Storage API: local storage and session storage
• Learn how HTTP Cookies work
• The History API
• The WebP Image Format
• XMLHttpRequest (XHR)
• An in-depth SVG tutorial
• What are Data URLs
• Roadmap to learn the Web Platform
• CORS, Cross-Origin Resource Sharing
• Web Workers
• The requestAnimationFrame() guide
• What is the Doctype
• Working with the DevTools Console and the Console API
• The Speech Synthesis API
• How to wait for the DOM ready event in plain JavaScript
• How to add a class to a DOM element
• How to loop over DOM elements from querySelectorAll
• How to remove a class from a DOM element
• How to check if a DOM element has a class
• How to change a DOM node value
• How to add a click event to a list of DOM elements returned from querySelectorAll
• WebRTC, the Real Time Web API
• How to get the scroll position of an element in JavaScript
• How to replace a DOM element
• How to only accept images in an input file field
• Why use a preview version of a browser?
• The Blob Object
• The File Object
• The FileReader Object
• The FileList Object
• ArrayBuffer
• ArrayBufferView
• The URL Object
• Typed Arrays
• The DataView Object
• The BroadcastChannel API
• The Streams API
• The FormData Object
• The Navigator Object
• How to use the Geolocation API
• How to use getUserMedia()
• How to use the Drag and Drop API
• How to work with scrolling on Web Pages
• Handling forms in JavaScript
• Keyboard events
• Mouse events
• Touch events
• How to remove all children from a DOM element
• How to create an HTML attribute using vanilla Javascript
• How to check if a checkbox is checked using JavaScript?
• How to copy to the clipboard using JavaScript
• How to disable a button using JavaScript
• How to make a page editable in the browser
• How to get query string values in JavaScript with URLSearchParams
• How to remove all CSS from a page at once
• How to use insertAdjacentHTML
• Safari, warn before quitting
• How to add an image to the DOM using JavaScript
• How to reset a form
• How to use Google Fonts