Common events

Following is a list of common events broadcast by various classes. Every component should try to broadcast these events if they make sense for that component. This is not a complete list of events for all components, just ones that are likely to be reused by other components. Even though some events specify no parameters, all events have an implicit parameter: a reference to the object broadcasting the event.

Event	Parameters	Use
`click`	None	Used by Button, or whenever a mouse click has no other meaning.
`scroll`	`Scrollbar.lineUp`, `lineDown`, `pageUp`, `pageDown`, `thumbTrack`, `thumbPosition`, `endScroll`, `toTop`, `toBottom`, `lineLeft`, `lineRight`, `pageLeft`, `pageRight`, `toLeft`, `toRight`	Used by ScrollBar and by other controls that cause scrolling (scroll "bumpers" on a scrolling pop-up menu).
`change`	None	Used by List, ComboBox, and other text entry components.
`maxChars`	None	Used when user tries to enter too many characters in text entry components.

In addition, because of inheritance from UIComponent, all components broadcast the following events:

UIComponent event	Description
`load`	The component is creating or loading its subobjects.
`unload`	The component is unloading its subobjects.
`focusIn`	The component now has the input focus. Some HTML-equivalent components (ListBox, ComboBox, Button, Text) might also emit focus, but all emit DOMFocusIn
`focusOut`	The component has lost the input focus.
`move`	The component has been moved to a new location.
`resize`	The component has been resized.

The following table describes common key events:

Key events	Description
`keyDown`	A key has been pressed. The `code` property contains the key code and the `ascii` property contains the ASCII code of the key pressed. Do not check with the low-level Key object, because the event might not have been generated by the Key object.
`keyUp`	A key has been released.