This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
The search event is fired when a search is initiated on an <input> of type="search". There are several ways a search can be initiated, such as by pressing Enter while the <input> is focused, or, if the incremental attribute is present, after a UA-defined timeout elapses since the most recent keystroke (with new keystrokes resetting the timeout; so the firing of the event is debounced). This event is currently only supported by WebKit (Safari) and Blink (Chrome, Opera).