Class Event

Object
   |
   +--Event

class Event

Defined in events.js

Constructor Detail

Event

function Event()

addEventListener

void addEventListener(<DOMNode> element, <string> eventName, <Function> listener)

Adds an event listener to element. Does nothing if listener has already been registered for eventName events on element (ie. it is safe to register a listener twice for the same event—the listener will be called only once, not twice).

Note: element must have a unique .id attribute. The html member in Widget is guaranteed to have a unique id, but other DOM nodes may need to be given one.

Parameters:
element - the element of the DOM to which listener should be attached
eventName - the name of the event to which listener should listen
listener - the function to be called when events named eventName are raised on element

getEvent

DOMEvent getEvent(<DOMEvent> e)

Returns the event currently being raised. Some browsers (e.g Mozilla) will pass the event object to listeners as the first and only parameter. Other browsers (e.g. Internet Explorer) do not pass the event object that way and, instead, make it available in a global variable. To get a reference to the event object in a browser-independent way, declare listeners to accept one parameter, and then pass that parameter to Event.getEvent. The return value will be the proper event object. For example:

var html = ...; // some DOM node

// note that the listener is declared with one formal parameter
Event.addEventListener(html, 'someevent', function(e) {
    // at this point, e might refer to the event object, or it might be
    // undefined--it depends on the user's browser.

    var event = Event.getEvent(e);

    // event now refers to the event object, regardless of which browser the
    // user is running
});

Parameters:
e - the first parameter to an event listener

Returns:
the event object for the current event

getKeyCode

int getKeyCode(<DOMEvent> event)

Returns the key code of the key that was pressed when event happened. See KeyCode for some common key codes.

Parameters:
event - the event to query

Returns:
the key code

getMouseButton

Mouse getMouseButton(<DOMEvent> event)

Returns a code indicating which mouse button was depressed during event.

Parameters:
event - the event to query

Returns:
the mouse button that the user pressed

getMousePoint

Point getMousePoint(<DOMEvent> event)

Returns the co-ordinates of the mouse at the time of event in a Point of Pixels. The co-ordinates are relative to the browser's viewport (0, 0).

Parameters:
event - the event to query

Returns:
the mouse co-ordinates when event happened

getRelativeMousePoint

Point getRelativeMousePoint(<DOMNode> element, <DOMEvent> event)

Returns the co-ordinates of the mouse at the time of event relative to element. The co-ordinates are returned as a Point of Pixels.

Parameters:
element - the element to which the returned co-ordinates should be relative
event - the event that should be queried for co-ordinates

Returns:
the mouse co-ordinates when event happened, relative to element

isAltPressed

boolean isAltPressed(<DOMEvent> event)

Returns true if the user was holding down the Alt key while event took place, and false otherwise.

Parameters:
event - the event to be queried

Returns:
the alt-state at the time of event

See:
- Event.isCtrlPressed()
- Event.isShiftPressed()

isCtrlPressed

boolean isCtrlPressed(<DOMEvent> event)

Returns true if the user was holding down the Ctrl key while event took place, and false otherwise.

Parameters:
event - the event to be queried

Returns:
the ctrl-state at the time of event

See:
- Event.isAltPressed()
- Event.isShiftPressed()

isShiftPressed

boolean isShiftPressed(<DOMEvent> event)

Returns true if the user was holding down the Shift key while event took place, and false otherwise.

Parameters:
event - the event to be queried

Returns:
the shift-state at the time of event

See:
- Event.isCtrlPressed()
- Event.isAltPressed()

preventDefault

boolean preventDefault(<DOMEvent> event)

Prevents the default action associated with event from happening. To be effective in all browsers, the return value from preventDefault must be the return value of the event listener that is trying to prevent the default action.

Parameters:
event - the event whose default action should be blocked

Returns:
false

preventSelection

void preventSelection(<DOMNode> html)

Prevents text-selection on html and its descendants.

Parameters:
html - the element for which text-selection should be prohibited

removeEventListener

void removeEventListener(<DOMNode> element, <string> eventName, <Function> listener)

Removes an event listener from element. Does nothing if listener has not already been registered for eventName events on element (ie. it is safe to unregister the same listener twice).

Parameters:
element - the element of the DOM from which listener should be detached
eventName - the name of the event to which listener may be listening
listener - the function to unregister

stopPropagation

void stopPropagation(<DOMEvent> event)

Blocks event from bubbling any further up the document in a browser-independent way.

Parameters:
event - the event to "swallow"