DOMException

DOMException is a built-in error type defined by the Document Object Model specifications to represent errors that occur when interacting with the DOM and related web platform APIs. It is used by various APIs and methods to indicate that an operation could not be completed due to invalid state, insufficient permissions, or other constraints. In JavaScript, DOMException is an object that inherits from Error and is typically accessible as window.DOMException in browsers.

The constructor and properties of DOMException follow a simple pattern. The constructor is new DOMException(message, name), where the first argument is an optional human-friendly description and the second argument is the specific error name, such as NotFoundError, NotAllowedError, NotSupportedError, SecurityError, NetworkError, AbortError, or ConstraintError. The resulting object has a name property containing the error name and a message property with the description; a numeric code property exists in some environments but is deprecated in modern practice.

DOMException is used across many DOM and Web APIs to signal that an operation cannot proceed. The name property identifies the exact error, while the message provides additional context. Developers often handle these errors with try...catch blocks or by inspecting error.name in promise rejections or event handlers.

Compatibility and notes: DOMException has wide support in modern browsers. The numeric code property is largely obsolete, and code checks are generally discouraged in favor of examining the name. While developers may rarely construct DOMException manually, understanding its presence helps in debugging APIs and in implementing polyfills or error-mapping layers that emulate DOM behavior.