The unload event is raised when the window is unloading its content and resources. The resources removal is processed after the unload event occurs.
Note that as of Firefox 40, IndexedDB transactions have relaxed durability guarantees to increase performance (see bug 1112702.) Previously in a readwrite transaction IDBTransaction.oncomplete was fired only when all data was guaranteed to have been flushed to disk. In Firefox 40+ the complete event is fired after the OS has been told to write the data but potentially before that data has actually been flushed to disk. The complete event may thus be delivered quicker than before, however, there exists a small chance that the entire transaction will be lost if the OS crashes or there is a loss of system power before the data is flushed to disk. Since such catastrophic events are rare most consumers should not need to concern themselves further.
The Window.prompt() displays a dialog with an optional message prompting the user to input some text.
XMLHttpRequest makes sending HTTP requests very easy.  You simply create an instance of the object, open a URL, and send the request.  The HTTP status of the result, as well as the result's contents, are available in the request object when the transaction is completed. This page outlines some of the common, and even slightly obscure, use cases for this powerful JavaScript object.
Repeatedly calls a function or executes a code snippet, with a fixed time delay between each call. Returns an intervalID.
Sets a timer which executes a function or specified piece of code once after the timer expires.
The HTML element <input> is used to create interactive controls for web-based forms in order to accept data from the user. How an <input> works varies considerably depending on the value of its type attribute.