event.js

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         */
        var counter = 0;

        return { // PREPROCESS

            /**
             * The number of times we should look for elements that are not
             * in the DOM at the time the event is requested after the document
             * has been loaded.  The default is 200@amp;50 ms, so it will poll
             * for 10 seconds or until all outstanding handlers are bound
             * (whichever comes first).
             * @property POLL_RETRYS
             * @type int
             */
            POLL_RETRYS: 200,

            /**
             * The poll interval in milliseconds
             * @property POLL_INTERVAL
             * @type int
             */
            POLL_INTERVAL: 50,

            /**
             * Element to bind, int constant
             * @property EL
             * @type int
             */
            EL: 0,

            /**
             * Type of event, int constant
             * @property TYPE
             * @type int
             */
            TYPE: 1,

            /**
             * Function to execute, int constant
             * @property FN
             * @type int
             */
            FN: 2,

            /**
             * Function wrapped for scope correction and cleanup, int constant
             * @property WFN
             * @type int
             */
            WFN: 3,

            /**
             * Object passed in by the user that will be returned as a
             * parameter to the callback, int constant
             * @property SCOPE
             * @type int
             */
            SCOPE: 3,

            /**
             * Adjusted scope, either the element we are registering the event
             * on or the custom object passed in by the listener, int constant
             * @property ADJ_SCOPE
             * @type int
             */
            ADJ_SCOPE: 4,

            /**
             * Safari detection is necessary to work around the preventDefault
             * bug that makes it so you can't cancel a href click from the
             * handler.  There is not a capabilities check we can use here.
             * @property isSafari
             * @private
             */
            isSafari: (/Safari|Konqueror|KHTML/gi).test(navigator.userAgent),

            /**
             * IE detection needed to properly calculate pageX and pageY.
             * capabilities checking didn't seem to work because another
             * browser that does not provide the properties have the values
             * calculated in a different manner than IE.
             * @property isIE
             * @private
             */
            isIE: (!this.isSafari && !navigator.userAgent.match(/opera/gi) &&
                    navigator.userAgent.match(/msie/gi)),

            /**
             * @method addDelayedListener
             * @private
             */
            addDelayedListener: function(el, sType, fn, oScope, bOverride) {
                delayedListeners[delayedListeners.length] =
                    [el, sType, fn, oScope, bOverride];

                // If this happens after the inital page load, we need to
                // reset the poll counter so that we continue to search for
                // the element for a fixed period of time.
                if (loadComplete) {
                    retryCount = this.POLL_RETRYS;
                    this.startTimeout(0);
                    // this._tryPreloadAttach();
                }
            },

            /**
             * @method startTimeout
             * @private
             */
            startTimeout: function(interval) {
                var i = (interval || interval === 0) ? interval : this.POLL_INTERVAL;
                var self = this;
                var callback = function() { self._tryPreloadAttach(); };
                this.timeout = setTimeout(callback, i);
            },

            /**
             * Executes the supplied callback when the item with the supplied
             * id is found.  This is meant to be used to execute behavior as
             * soon as possible as the page loads.  If you use this after the
             * initial page load it will poll for a fixed time for the element.
             * The number of times it will poll and the frequency are
             * configurable.  By default it will poll for 10 seconds.
             *
             * @method onAvailable
             *
             * @param {string}   p_id the id of the element to look for.
             * @param {function} p_fn what to execute when the element is found.
             * @param {object}   p_obj an optional object to be passed back as
             *                   a parameter to p_fn.
             * @param {boolean}  p_override If set to true, p_fn will execute
             *                   in the scope of p_obj
             *
             */
            onAvailable: function(p_id, p_fn, p_obj, p_override) {
                onAvailStack.push( { id:       p_id,
                                     fn:       p_fn,
                                     obj:      p_obj,
                                     override: p_override } );

                retryCount = this.POLL_RETRYS;
                this.startTimeout(0);
                // this._tryPreloadAttach();
            },

            /**
             * Appends an event handler
             *
             * @method addListener
             *
             * @param {Object}   el        The html element to assign the
             *                             event to
             * @param {String}   sType     The type of event to append
             * @param {Function} fn        The method the event invokes
             * @param {Object}   oScope    An arbitrary object that will be
             *                             passed as a parameter to the handler
             * @param {boolean}  bOverride If true, the obj passed in becomes
             *                             the execution scope of the listener
             * @return {boolean} True if the action was successful or defered,
             *                        false if one or more of the elements
             *                        could not have the event bound to it.
             */
            addListener: function(el, sType, fn, oScope, bOverride) {

                if (!fn || !fn.call) {
                    return false;
                }

                // The el argument can be an array of elements or element ids.
                if ( this._isValidCollection(el)) {
                    var ok = true;
                    for (var i=0,len=el.length; i<len; ++i) {
                        ok = ( this.on(el[i],
                                       sType,
                                       fn,
                                       oScope,
                                       bOverride) && ok );
                    }
                    return ok;

                } else if (typeof el == "string") {
                    var oEl = this.getEl(el);
                    // If the el argument is a string, we assume it is
                    // actually the id of the element.  If the page is loaded
                    // we convert el to the actual element, otherwise we
                    // defer attaching the event until onload event fires

                    // check to see if we need to delay hooking up the event
                    // until after the page loads.
                    if (loadComplete && oEl) {
                        el = oEl;
                    } else {
                        // defer adding the event until onload fires
                        this.addDelayedListener(el,
                                                sType,
                                                fn,
                                                oScope,
                                                bOverride);

                        return true;
                    }
                }

                // Element should be an html element or an array if we get
                // here.
                if (!el) {
                    return false;
                }

                // we need to make sure we fire registered unload events
                // prior to automatically unhooking them.  So we hang on to
                // these instead of attaching them to the window and fire the
                // handles explicitly during our one unload event.
                if ("unload" == sType && oScope !== this) {
                    unloadListeners[unloadListeners.length] =
                            [el, sType, fn, oScope, bOverride];
                    return true;
                }

                // if the user chooses to override the scope, we use the custom
                // object passed in, otherwise the executing scope will be the
                // HTML element that the event is registered on
                var scope = (bOverride) ? oScope : el;

                // wrap the function so we can return the oScope object when
                // the event fires;
                var wrappedFn = function(e) {
                        return fn.call(scope, YAHOO.util.Event.getEvent(e),
                                oScope);
                    };

                var li = [el, sType, fn, wrappedFn, scope];
                var index = listeners.length;
                // cache the listener so we can try to automatically unload
                listeners[index] = li;

                if (this.useLegacyEvent(el, sType)) {
                    var legacyIndex = this.getLegacyIndex(el, sType);

                    // Add a new dom0 wrapper if one is not detected for this
                    // element
                    if ( legacyIndex == -1 ||
                                el != legacyEvents[legacyIndex][0] ) {

                        legacyIndex = legacyEvents.length;
                        legacyMap[el.id + sType] = legacyIndex;

                        // cache the signature for the DOM0 event, and
                        // include the existing handler for the event, if any
                        legacyEvents[legacyIndex] =
                            [el, sType, el["on" + sType]];
                        legacyHandlers[legacyIndex] = [];

                        el["on" + sType] =
                            function(e) {
                                YAHOO.util.Event.fireLegacyEvent(
                                    YAHOO.util.Event.getEvent(e), legacyIndex);
                            };
                    }

                    // add a reference to the wrapped listener to our custom
                    // stack of events
                    //legacyHandlers[legacyIndex].push(index);
                    legacyHandlers[legacyIndex].push(li);

                // DOM2 Event model
                } else if (el.addEventListener) {
                    el.addEventListener(sType, wrappedFn, false);
                // IE
                } else if (el.attachEvent) {
                    el.attachEvent("on" + sType, wrappedFn);
                }

                return true;

            },

            /**
             * When using legacy events, the handler is routed to this object
             * so we can fire our custom listener stack.
             * @method fireLegacyEvent
             * @private
             */
            fireLegacyEvent: function(e, legacyIndex) {
                var ok = true;

                var le = legacyHandlers[legacyIndex];
                for (var i=0,len=le.length; i<len; ++i) {
                    var li = le[i];
                    if ( li && li[this.WFN] ) {
                        var scope = li[this.ADJ_SCOPE];
                        var ret = li[this.WFN].call(scope, e);
                        ok = (ok && ret);
                    }
                }

                return ok;
            },

            /**
             * Returns the legacy event index that matches the supplied
             * signature
             * @method getLegacyIndex
             * @private
             */
            getLegacyIndex: function(el, sType) {
                var key = this.generateId(el) + sType;
                if (typeof legacyMap[key] == "undefined") {
                    return -1;
                } else {
                    return legacyMap[key];
                }
            },

            /**
             * Logic that determines when we should automatically use legacy
             * events instead of DOM2 events.
             * @method useLegacyEvent
             * @private
             */
            useLegacyEvent: function(el, sType) {
                if (!el.addEventListener && !el.attachEvent) {
                    return true;
                } else if (this.isSafari) {
                    if ("click" == sType || "dblclick" == sType) {
                        return true;
                    }
                }
                return false;
            },

            /**