In JavaScript, BOM stands for Browser Object Model. It is a browser-specific convention referring to all the objects exposed by the web browser. The BOM allows JavaScript to interact with the browser and provides objects that expose the web browsers functionality. The BOM is different from the Document Object Model (DOM), which deals with the document and the HTML elements themselves. The BOM deals with browser components aside from the document, like history, location, navigator, and screen. The window object is part of the BOM and is supported by all browsers. It represents the browsers window, and all global JavaScript objects, functions, and variables automatically become members of the window object. Since there is no standard for implementation and no strict definition, browser vendors are free to implement the BOM in any way they wish.