The BOM (Browser Object Model) contains objects that represent the current browser window and components; objects that model things like history, device’s screen, etc

The topmost object in BOM is the window object, which represents the current browser window or tab.

• Document: represents current web page.
• History: represents pages in browser history.
• Location: represents URL of current page.
• Navigator: represents information about browser.
• Screen: represents device’s display information.