event.js

一个使用yui-ext库

                                scope = l[EU.ADJ_SCOPE];
                            }
                        }
                        l[EU.FN].call(scope, EU.getEvent(e), l[EU.OBJ] );
                        unloadListeners[i] = null;
                        l=null;
                        scope=null;
                    }
                }

                unloadListeners = null;

                if (listeners && listeners.length > 0) {
                    j = listeners.length;
                    while (j) {
                        index = j-1;
                        l = listeners[index];
                        if (l) {
                            EU.removeListener(l[EU.EL], l[EU.TYPE], 
                                    l[EU.FN], index);
                        } 
                        j = j - 1;
                    }
                    l=null;

                    EU.clearCache();
                }

                for (i=0,len=legacyEvents.length; i<len; ++i) {
                    // dereference the element
                    //delete legacyEvents[i][0];
                    legacyEvents[i][0] = null;

                    // delete the array item
                    //delete legacyEvents[i];
                    legacyEvents[i] = null;
                }

                legacyEvents = null;

                EU._simpleRemove(window, "unload", EU._unload);

            },

            /**
             * Returns scrollLeft
             * @method _getScrollLeft
             * @static
             * @private
             */
            _getScrollLeft: function() {
                return this._getScroll()[1];
            },

            /**
             * Returns scrollTop
             * @method _getScrollTop
             * @static
             * @private
             */
            _getScrollTop: function() {
                return this._getScroll()[0];
            },

            /**
             * Returns the scrollTop and scrollLeft.  Used to calculate the 
             * pageX and pageY in Internet Explorer
             * @method _getScroll
             * @static
             * @private
             */
            _getScroll: function() {
                var dd = document.documentElement, db = document.body;
                if (dd && (dd.scrollTop || dd.scrollLeft)) {
                    return [dd.scrollTop, dd.scrollLeft];
                } else if (db) {
                    return [db.scrollTop, db.scrollLeft];
                } else {
                    return [0, 0];
                }
            },
            
            /**
             * Used by old versions of CustomEvent, restored for backwards
             * compatibility
             * @method regCE
             * @private
             */
            regCE: function() {
                // does nothing
            },

            /**
             * Adds a DOM event directly without the caching, cleanup, scope adj, etc
             *
             * @method _simpleAdd
             * @param {HTMLElement} el      the element to bind the handler to
             * @param {string}      sType   the type of event handler
             * @param {function}    fn      the callback to invoke
             * @param {boolen}      capture capture or bubble phase
             * @static
             * @private
             */
            _simpleAdd: function () {
                if (window.addEventListener) {
                    return function(el, sType, fn, capture) {
                        el.addEventListener(sType, fn, (capture));
                    };
                } else if (window.attachEvent) {
                    return function(el, sType, fn, capture) {
                        el.attachEvent("on" + sType, fn);
                    };
                } else {
                    return function(){};
                }
            }(),

            /**
             * Basic remove listener
             *
             * @method _simpleRemove
             * @param {HTMLElement} el      the element to bind the handler to
             * @param {string}      sType   the type of event handler
             * @param {function}    fn      the callback to invoke
             * @param {boolen}      capture capture or bubble phase
             * @static
             * @private
             */
            _simpleRemove: function() {
                if (window.removeEventListener) {
                    return function (el, sType, fn, capture) {
                        el.removeEventListener(sType, fn, (capture));
                    };
                } else if (window.detachEvent) {
                    return function (el, sType, fn) {
                        el.detachEvent("on" + sType, fn);
                    };
                } else {
                    return function(){};
                }
            }()
        };

    }();

    (function() {
        var EU = YAHOO.util.Event;

        /**
         * YAHOO.util.Event.on is an alias for addListener
         * @method on
         * @see addListener
         * @static
         */
        EU.on = EU.addListener;

        // YAHOO.mix(EU, YAHOO.util.EventProvider.prototype);
        // EU.createEvent("DOMContentReady");
        // EU.subscribe("DOMContentReady", EU._load);

        if (document && document.body) {
            EU._load();
        } else {
            // EU._simpleAdd(document, "DOMContentLoaded", EU._load);
            EU._simpleAdd(window, "load", EU._load);
        }
        EU._simpleAdd(window, "unload", EU._unload);
        EU._tryPreloadAttach();
    })();
}

/**
 * The CustomEvent class lets you define events for your application
 * that can be subscribed to by one or more independent component.
 *
 * @param {String}  type The type of event, which is passed to the callback
 *                  when the event fires
 * @param {Object}  oScope The context the event will fire from.  "this" will
 *                  refer to this object in the callback.  Default value: 
 *                  the window object.  The listener can override this.
 * @param {boolean} silent pass true to prevent the event from writing to
 *                  the debugsystem
 * @param {int}     signature the signature that the custom event subscriber
 *                  will receive. YAHOO.util.CustomEvent.LIST or 
 *                  YAHOO.util.CustomEvent.FLAT.  The default is
 *                  YAHOO.util.CustomEvent.LIST.
 * @namespace YAHOO.util
 * @class CustomEvent
 * @constructor
 */
YAHOO.util.CustomEvent = function(type, oScope, silent, signature) {

    /**
     * The type of event, returned to subscribers when the event fires
     * @property type
     * @type string
     */
    this.type = type;

    /**
     * The scope the the event will fire from by default.  Defaults to the window 
     * obj
     * @property scope
     * @type object
     */
    this.scope = oScope || window;

    /**
     * By default all custom events are logged in the debug build, set silent
     * to true to disable debug outpu for this event.
     * @property silent
     * @type boolean
     */
    this.silent = silent;

    /**
     * Custom events support two styles of arguments provided to the event
     * subscribers.  
     * <ul>
     * <li>YAHOO.util.CustomEvent.LIST: 
     *   <ul>
     *   <li>param1: event name</li>
     *   <li>param2: array of arguments sent to fire</li>
     *   <li>param3: <optional> a custom object supplied by the subscriber</li>
     *   </ul>
     * </li>
     * <li>YAHOO.util.CustomEvent.FLAT
     *   <ul>
     *   <li>param1: the first argument passed to fire.  If you need to
     *           pass multiple parameters, use and array or object literal</li>
     *   <li>param2: <optional> a custom object supplied by the subscriber</li>
     *   </ul>
     * </li>
     * </ul>
     *   @property signature
     *   @type int
     */
    this.signature = signature || YAHOO.util.CustomEvent.LIST;

    /**
     * The subscribers to this event
     * @property subscribers
     * @type Subscriber[]
     */
    this.subscribers = [];

    if (!this.silent) {
    }

    var onsubscribeType = "_YUICEOnSubscribe";

    // Only add subscribe events for events that are not generated by 
    // CustomEvent
    if (type !== onsubscribeType) {

        /**
         * Custom events provide a custom event that fires whenever there is
         * a new subscriber to the event.  This provides an opportunity to
         * handle the case where there is a non-repeating event that has
         * already fired has a new subscriber.  
         *
         * @event subscribeEvent
         * @type YAHOO.util.CustomEvent
         * @param {Function} fn The function to execute
         * @param {Object}   obj An object to be passed along when the event 
         *                       fires
         * @param {boolean|Object}  override If true, the obj passed in becomes 
         *                                   the execution scope of the listener.
         *                                   if an object, that object becomes the
         *                                   the execution scope.
         */
        this.subscribeEvent = 
                new YAHOO.util.CustomEvent(onsubscribeType, this, true);

    } 
};

/**
 * Subscriber listener sigature constant.  The LIST type returns three
 * parameters: the event type, the array of args passed to fire, and
 * the optional custom object
 * @property YAHOO.util.CustomEvent.LIST
 * @static
 * @type int
 */
YAHOO.util.CustomEvent.LIST = 0;

/**
 * Subscriber listener sigature constant.  The FLAT type returns two
 * parameters: the first argument passed to fire and the optional 
 * custom object
 * @property YAHOO.util.CustomEvent.FLAT
 * @static
 * @type int
 */
YAHOO.util.CustomEvent.FLAT = 1;

YAHOO.util.CustomEvent.prototype = {

    /**
     * Subscribes the caller to this event
     * @method subscribe
     * @param {Function} fn        The function to execute
     * @param {Object}   obj       An object to be passed along when the event 
     *                             fires
     * @param {boolean|Object}  override If true, the obj passed in becomes 
     *                                   the execution scope of the listener.
     *                                   if an object, that object becomes the
     *                                   the execution scope.
     */
    subscribe: function(fn, obj, override) {
        if (this.subscribeEvent) {
            this.subscribeEvent.fire(fn, obj, override);
        }

        this.subscribers.push( new YAHOO.util.Subscriber(fn, obj, override) );
    },

    /**
     * Unsubscribes subscribers.
     * @method unsubscribe
     * @param {Function} fn  The subscribed function to remove, if not supplied
     *                       all will be removed
     * @param {Object}   obj  The custom object passed to subscribe.  This is
     *                        optional, but if supplied will be used to
     *                        disambiguate multiple listeners that are the same
     *                        (e.g., you subscribe many object using a function
     *                        that lives on the prototype)
     * @return {boolean} True if the subscriber was found and detached.
     */
    unsubscribe: function(fn, obj) {

        if (!fn) {
            return this.unsubscribeAll();
        }

        var found = false;
        for (var i=0, len=this.subscribers.length; i<len; ++i) {
            var s = this.subscribers[i];
            if (s && s.contains(fn, obj)) {
                this._delete(i);
                found = true;
            }
        }

        return found;
    },

    /**
     * Notifies the subscribers.  The callback functions will be executed
     * from the scope specified when the event was created, and with the 
     * following parameters:
     *   <ul>
     *   <li>The type of event</li>
     *   <li>All of the arguments fire() was executed with as an array</li>
     *   <li>The custom object (if any) that was passed into the subscribe() 
     *       method</li>
     *   </ul>
     * @method fire 
     * @param {Object*} arguments an arbitrary set of parameters to pass to 
     *                            the handler.
     * @return {boolean} false if one of the subscribers returned false, 
     *                   true otherwise
     */
    fire: function() {
        var len=this.subscribers.length;
        if (!len && this.silent) {
            return true;
        }

        var args=[], ret=true, i;

        for (i=0; i<arguments.length; ++i) {
            args.push(arguments[i]);
        }

        var argslength = args.length;