Later the core part of the language became standardized by ECMA and is named “ECMAScript“.
- ECMAScript : core syntax and semantics
- DOM (Document Object Model) : Document structure and navigation
- BOM (Browser Object Model) : Browser specific information
ECMAScript defines the language itself, but not the host environment.
DOM is an API (Application Programming Interface) for XML. DOM defines the document using hierarchical elements.
- Level 1 (1998) : Core (structure and navigation)
- Level 2 (2000) : Views, Events, Style
- Level 3 (2004) : Load/Save, Validation
BOM is the least standardized area.
In web browsers, the “window” is the main (global) object through which you can access all browser related information.
- history : the URLs that have been visited before and after the current page
- location : the current URL of the browser window
- navigator : the object about the browser information
- screen : the user’s screen object
Also BOM provides cookies and other custom objects such as XMLHttpRequest.