Event Triggers

The names of some event handlers clearly describe what actions trigger the event. (It doesn’t take rocket science to figure that an onClick event is fired when something is clicked.) Other events are a little less intuitive.

Remember, also, that event names change in different environments. For example, the JavaScript onBlur event is called the LostFocus event in most Windows programming environments.

Table 8-2 shows JavaScript event handlers and the actions that fire them.

Table 8-2: Events and Their Triggers

Event	Action That Fires the Event
onAbort	The loading of an image is interrupted.
onBlur	The object loses input focus—typically because the user moves to another screen element using the mouse or keyboard.
onChange	In a select list, the user selects or deselects an element. In a text box, the user enters or changes text and causes focus to move to another object.
onClick	The user clicks once. You can return false in code to cancel a default action.
onDblClick	The user clicks twice.
onError	An error occurs while loading an image.
onFocus	The object gains input focus—usually because the user has moved to the object using the mouse or keyboard.
onKeyDown	The user presses a key. You can return false in code to cancel.
onKeyPress	The user presses or releases a key. (onKeyPress is the same as onKeyDown or onKeyUp.)
onKeyUp	The user releases a key.
onLoad	A document or image finishes loading.
onMouseDown	The user presses a mouse button.
onMouseOut	The mouse is moved off an element.
onMouseOver	The mouse is moved over an element. (For links, to prevent the URL from appearing in the status bar, return true.)
onMouseUp	The user releases a mouse button.
onReset	A form reset is requested.
onResize	A window is resized.
onSubmit	A form submission is requested.
onUnload	A document is unloaded.