The read-only property ValidityState.badInput indicates if the user has provided input that the browser is unable to convert. For example, if you have a mail input element whose content does not have a '@'.
The Window.console read-only property returns a reference to the Console object, which provides methods for logging information to the browser's console. These methods are intended for debugging purposes only and should not be relied on for presenting information to end users.
The Window.self read-only property returns the window itself, as a WindowProxy. It can be used with dot notation on a window object (that is, window.self) or standalone (self). The advantage of the standalone notation is that a similar notation exists for non-window contexts, such as in Web Workers. By using self, you can refer to the global scope in a way that will work not only in a window context (self will resolve to window.self) but also in a worker context (self will then resolve to WorkerGlobalScope.self).