JavaScript window Object

Written by Swapnil RajaPublished 24 Aug 2026

window represents the browser tab and is the top of the global scope.

Every global variable and function is technically a property of it.

You rarely write window. yourself, but it is always there.

Example

javascript

console.log(typeof window);
console.log(typeof window.document);

Both are object.

What window Provides

window.innerWidth and innerHeight - the visible area.

window.location - the current URL.

window.document - the page itself.

Syntax

PreviousJavaScript Storage Events NextJavaScript location Object

Complete Example

html

<!DOCTYPE html>
<html>
<head>
  <title>JavaScript window Object</title>
</head>
<body>

  <h1>The window Object</h1>

  <p id="out"></p>

  <script>
    document.getElementById("out").innerHTML =
      "Window width: " + window.innerWidth +
      "<br>Window height: " + window.innerHeight +
      "<br>Current page: " + window.location.href;
  </script>

</body>
</html>

JavaScript window Object

Example

What window Provides

Syntax

Globals Live on window

Example

let and const Do Not Attach

Example

The Viewport Size

Example

Reading the URL

Example

alert, confirm and prompt

Example

Complete Example

Try It Yourself

Important Points

Conclusion