JavaScript BOM

JavaScript BOM (Browser Object Model)

The Browser Object Model (BOM) allows JavaScript to interact with the browser itself, not just the webpage.

Through BOM, JavaScript can:

•  Control browser windows
•  Access browser history
•  Work with URL and location
•  Detect browser information
•  Access local/session storage

window Object

The window object is the top-level object in the browser.
Everything in BOM is part of window.

Example:

 Key BOM Components

 1. window.alert() – Show Message Box

 2. window.confirm() – Ask Yes/No Question

If user clicks:

•  OK → true

•  Cancel → false

 3. window.prompt() – Input From User

 4. window.open() and window.close()

 5. window.setTimeout() — Delay Execution

 6. window.setInterval() — Repeat Execution

 Location Object

Used to work with the current URL.

Redirect to another page:

 History Object

Used to navigate browser history.

 Navigator Object

Gives browser and device info.

 Storage (Web Storage)

Local Storage (saved permanently)

Session Storage (removed after tab closes)

 Summary Table