event.js

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

                    // before the window load notification
                    EU._tryPreloadAttach();

                    // Remove the listener to assist with the IE memory issue, but not
                    // for other browsers because FF 1.0x does not like it.
                    //if (this.isIE) {
                        //EU._simpleRemove(window, "load", EU._load);
                    //}
                }
            },

            /**
             * Fires the DOMReady event listeners the first time the document is
             * usable.
             * @method _ready
             * @static
             * @private
             */
            _ready: function(e) {
                var EU = YAHOO.util.Event;
                if (!EU.DOMReady) {
                    EU.DOMReady=true;

                    // Fire the content ready custom event
                    EU.DOMReadyEvent.fire();

                    // Remove the DOMContentLoaded (FF/Opera)
                    EU._simpleRemove(document, "DOMContentLoaded", EU._ready);
                }
            },

            /**
             * Polling function that runs before the onload event fires, 
             * attempting to attach to DOM Nodes as soon as they are 
             * available
             * @method _tryPreloadAttach
             * @static
             * @private
             */
            _tryPreloadAttach: function() {

                if (this.locked) {
                    return false;
                }

                if (this.isIE) {
                    // Hold off if DOMReady has not fired and check current
                    // readyState to protect against the IE operation aborted
                    // issue.
                    //if (!this.DOMReady || "complete" !== document.readyState) {
                    if (!this.DOMReady) {
                        this.startInterval();
                        return false;
                    }
                }

                this.locked = true;


                // keep trying until after the page is loaded.  We need to 
                // check the page load state prior to trying to bind the 
                // elements so that we can be certain all elements have been 
                // tested appropriately
                var tryAgain = !loadComplete;
                if (!tryAgain) {
                    tryAgain = (retryCount > 0);
                }

                // onAvailable
                var notAvail = [];

                var executeItem = function (el, item) {
                    var scope = el;
                    if (item.override) {
                        if (item.override === true) {
                            scope = item.obj;
                        } else {
                            scope = item.override;
                        }
                    }
                    item.fn.call(scope, item.obj);
                };

                var i,len,item,el;

                // onAvailable
                for (i=0,len=onAvailStack.length; i<len; ++i) {
                    item = onAvailStack[i];
                    if (item && !item.checkReady) {
                        el = this.getEl(item.id);
                        if (el) {
                            executeItem(el, item);
                            onAvailStack[i] = null;
                        } else {
                            notAvail.push(item);
                        }
                    }
                }

                // onContentReady
                for (i=0,len=onAvailStack.length; i<len; ++i) {
                    item = onAvailStack[i];
                    if (item && item.checkReady) {
                        el = this.getEl(item.id);

                        if (el) {
                            // The element is available, but not necessarily ready
                            // @todo should we test parentNode.nextSibling?
                            if (loadComplete || el.nextSibling) {
                                executeItem(el, item);
                                onAvailStack[i] = null;
                            }
                        } else {
                            notAvail.push(item);
                        }
                    }
                }

                retryCount = (notAvail.length === 0) ? 0 : retryCount - 1;

                if (tryAgain) {
                    // we may need to strip the nulled out items here
                    this.startInterval();
                } else {
                    clearInterval(this._interval);
                    this._interval = null;
                }

                this.locked = false;

                return true;

            },

            /**
             * Removes all listeners attached to the given element via addListener.
             * Optionally, the node's children can also be purged.
             * Optionally, you can specify a specific type of event to remove.
             * @method purgeElement
             * @param {HTMLElement} el the element to purge
             * @param {boolean} recurse recursively purge this element's children
             * as well.  Use with caution.
             * @param {string} sType optional type of listener to purge. If
             * left out, all listeners will be removed
             * @static
             */
            purgeElement: function(el, recurse, sType) {
                var oEl = (YAHOO.lang.isString(el)) ? this.getEl(el) : el;
                var elListeners = this.getListeners(oEl, sType), i, len;
                if (elListeners) {
                    for (i=0,len=elListeners.length; i<len ; ++i) {
                        var l = elListeners[i];
                        // can't use the index on the changing collection
                        this.removeListener(oEl, l.type, l.fn, l.index);
                        //this.removeListener(oEl, l.type, l.fn);
                    }
                }

                if (recurse && oEl && oEl.childNodes) {
                    for (i=0,len=oEl.childNodes.length; i<len ; ++i) {
                        this.purgeElement(oEl.childNodes[i], recurse, sType);
                    }
                }
            },

            /**
             * Returns all listeners attached to the given element via addListener.
             * Optionally, you can specify a specific type of event to return.
             * @method getListeners
             * @param el {HTMLElement|string} the element or element id to inspect 
             * @param sType {string} optional type of listener to return. If
             * left out, all listeners will be returned
             * @return {Object} the listener. Contains the following fields:
             * &nbsp;&nbsp;type:   (string)   the type of event
             * &nbsp;&nbsp;fn:     (function) the callback supplied to addListener
             * &nbsp;&nbsp;obj:    (object)   the custom object supplied to addListener
             * &nbsp;&nbsp;adjust: (boolean|object)  whether or not to adjust the default scope
             * &nbsp;&nbsp;scope: (boolean)  the derived scope based on the adjust parameter
             * &nbsp;&nbsp;index:  (int)      its position in the Event util listener cache
             * @static
             */           
            getListeners: function(el, sType) {
                var results=[], searchLists;
                if (!sType) {
                    searchLists = [listeners, unloadListeners];
                } else if (sType === "unload") {
                    searchLists = [unloadListeners];
                } else {
                    searchLists = [listeners];
                }

                var oEl = (YAHOO.lang.isString(el)) ? this.getEl(el) : el;

                for (var j=0;j<searchLists.length; j=j+1) {
                    var searchList = searchLists[j];
                    if (searchList && searchList.length > 0) {
                        for (var i=0,len=searchList.length; i<len ; ++i) {
                            var l = searchList[i];
                            if ( l  && l[this.EL] === oEl && 
                                    (!sType || sType === l[this.TYPE]) ) {
                                results.push({
                                    type:   l[this.TYPE],
                                    fn:     l[this.FN],
                                    obj:    l[this.OBJ],
                                    adjust: l[this.OVERRIDE],
                                    scope:  l[this.ADJ_SCOPE],
                                    index:  i
                                });
                            }
                        }
                    }
                }

                return (results.length) ? results : null;
            },

            /**
             * Removes all listeners registered by pe.event.  Called 
             * automatically during the unload event.
             * @method _unload
             * @static
             * @private
             */
            _unload: function(e) {

                var EU = YAHOO.util.Event, i, j, l, len, index;

                // execute and clear stored unload listeners
                for (i=0,len=unloadListeners.length; i<len; ++i) {
                    l = unloadListeners[i];
                    if (l) {
                        var scope = window;
                        if (l[EU.ADJ_SCOPE]) {
                            if (l[EU.ADJ_SCOPE] === true) {
                                scope = l[EU.UNLOAD_OBJ];
                            } else {
                                scope = l[EU.ADJ_SCOPE];
                            }
                        }
                        l[EU.FN].call(scope, EU.getEvent(e, l[EU.EL]), l[EU.UNLOAD_OBJ] );
                        unloadListeners[i] = null;
                        l=null;
                        scope=null;
                    }
                }

                unloadListeners = null;

                // call clearAttributes or remove listeners to handle IE memory leaks
                if (YAHOO.env.ua.ie && listeners && listeners.length > 0) {
                    j = listeners.length;
                    while (j) {
                        index = j-1;
                        l = listeners[index];
                        if (l) {
                            //try {
                                //l[EU.EL].clearAttributes(); // errors on window objects
                            //} catch(ex) {
                            EU.removeListener(l[EU.EL], l[EU.TYPE], l[EU.FN], index);
                            //}
                        } 
                        j--;
                    }
                    l=null;
                }

                /*
                // remove all listeners
                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;
                }
                */

                /*
                // kill legacy events
                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
             * @static
             * @deprecated still here for backwards compatibility
             */
            regCE: function() {
                // does nothing
            },

/*
            testIEReady: function (){
                var n = document.createElement('p'), ready = false;
                try {
                    // throws an error until the doc is ready
                    n.doScroll('left'); 
                    ready = true;
                } catch(ex){ 
                    // document is not ready
                }

                n = null;
                return ready;
            },
*/

            /**
             * Adds a DOM event directly without the caching, cleanup, scope adj, etc
             *
             * @method _simpleAdd
             * @param {