/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2000
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Tom Pixley <joki@netscape.com> (original author)
 *   Johnny Stenback <jst@netscape.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * the provisions above, a recipient may use your version of this file under
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 * ***** END LICENSE BLOCK ***** */

#include "domstubs.idl"

interface nsIDOMEventTarget;

/**
 * The nsIDOMEvent interface is the primary datatype for all events in
 * the Document Object Model.
 *
 * For more information on this interface please see 
 * http://www.w3.org/TR/DOM-Level-2-Events/
 */

[scriptable, uuid(548137e8-fd2c-48c4-8635-3033f7db79e0)]
interface nsIDOMEvent : nsISupports
{
  // PhaseType
  /**
   * The current event phase is the capturing phase.
   */
  const unsigned short      CAPTURING_PHASE                = 1;

  /**
   * The event is currently being evaluated at the target EventTarget.
   */
  const unsigned short      AT_TARGET                      = 2;

  /**
   * The current event phase is the bubbling phase.
   */
  const unsigned short      BUBBLING_PHASE                 = 3;

  /**
   * The name of the event (case-insensitive). The name must be an XML 
   * name.
   */
  readonly attribute DOMString          type;

  /**
   * Used to indicate the EventTarget to which the event was originally 
   * dispatched.
   */
  readonly attribute nsIDOMEventTarget  target;

  /**
   * Used to indicate the EventTarget whose EventListeners are currently 
   * being processed. This is particularly useful during capturing and 
   * bubbling.
   */
  readonly attribute nsIDOMEventTarget  currentTarget;

  /**
   * Used to indicate which phase of event flow is currently being 
   * evaluated.
   */
  readonly attribute unsigned short     eventPhase;

  /**
   * Used to indicate whether or not an event is a bubbling event. If the 
   * event can bubble the value is true, else the value is false.
   */
  readonly attribute boolean            bubbles;

  /**
   * Used to indicate whether or not an event can have its default action 
   * prevented. If the default action can be prevented the value is true, 
   * else the value is false.
   */
  readonly attribute boolean            cancelable;

  /**
   * Used to specify the time (in milliseconds relative to the epoch) at 
   * which the event was created. Due to the fact that some systems may 
   * not provide this information the value of timeStamp may be not 
   * available for all events. When not available, a value of 0 will be 
   * returned. Examples of epoch time are the time of the system start or 
   * 0:0:0 UTC 1st January 1970.
   */
  readonly attribute DOMTimeStamp       timeStamp;

  /**
   * The stopPropagation method is used prevent further propagation of an 
   * event during event flow. If this method is called by any 
   * EventListener the event will cease propagating through the tree. The 
   * event will complete dispatch to all listeners on the current 
   * EventTarget before event flow stops. This method may be used during 
   * any stage of event flow.
   */
  void                      stopPropagation();

  /**
   * If an event is cancelable, the preventDefault method is used to 
   * signify that the event is to be canceled, meaning any default action 
   * normally taken by the implementation as a result of the event will 
   * not occur. If, during any stage of event flow, the preventDefault 
   * method is called the event is canceled. Any default action associated 
   * with the event will not occur. Calling this method for a 
   * non-cancelable event has no effect. Once preventDefault has been 
   * called it will remain in effect throughout the remainder of the 
   * event's propagation. This method may be used during any stage of 
   * event flow.
   */
  void                      preventDefault();

  /**
   * The initEvent method is used to initialize the value of an Event 
   * created through the DocumentEvent interface. This method may only be 
   * called before the Event has been dispatched via the dispatchEvent 
   * method, though it may be called multiple times during that phase if 
   * necessary. If called multiple times the final invocation takes 
   * precedence. If called from a subclass of Event interface only the 
   * values specified in the initEvent method are modified, all other 
   * attributes are left unchanged.
   *
   * @param   eventTypeArg Specifies the event type. This type may be 
   *                       any event type currently defined in this 
   *                       specification or a new event type.. The string 
   *                       must be an XML name.
   *                       Any new event type must not begin with any 
   *                       upper, lower, or mixed case version of the 
   *                       string "DOM". This prefix is reserved for 
   *                       future DOM event sets. It is also strongly 
   *                       recommended that third parties adding their 
   *                       own events use their own prefix to avoid 
   *                       confusion and lessen the probability of 
   *                       conflicts with other new events.
   * @param   canBubbleArg Specifies whether or not the event can bubble.
   * @param   cancelableArg Specifies whether or not the event's default 
   *                        action can be prevented.
   */
  void                      initEvent(in DOMString eventTypeArg,
                                      in boolean canBubbleArg,
                                      in boolean cancelableArg);

  /**
   * Used to indicate whether preventDefault() has been called for this event.
   */
  readonly attribute boolean defaultPrevented;
};
