event.js

一个使用yui-ext库

             * @return {Date} the time of the event
             * @static
             */
            getTime: function(ev) {
                if (!ev.time) {
                    var t = new Date().getTime();
                    try {
                        ev.time = t;
                    } catch(ex) { 
                        this.lastError = ex;
                        return t;
                    }
                }

                return ev.time;
            },

            /**
             * Convenience method for stopPropagation + preventDefault
             * @method stopEvent
             * @param {Event} ev the event
             * @static
             */
            stopEvent: function(ev) {
                this.stopPropagation(ev);
                this.preventDefault(ev);
            },

            /**
             * Stops event propagation
             * @method stopPropagation
             * @param {Event} ev the event
             * @static
             */
            stopPropagation: function(ev) {
                if (ev.stopPropagation) {
                    ev.stopPropagation();
                } else {
                    ev.cancelBubble = true;
                }
            },

            /**
             * Prevents the default behavior of the event
             * @method preventDefault
             * @param {Event} ev the event
             * @static
             */
            preventDefault: function(ev) {
                if (ev.preventDefault) {
                    ev.preventDefault();
                } else {
                    ev.returnValue = false;
                }
            },
             
            /**
             * Finds the event in the window object, the caller's arguments, or
             * in the arguments of another method in the callstack.  This is
             * executed automatically for events registered through the event
             * manager, so the implementer should not normally need to execute
             * this function at all.
             * @method getEvent
             * @param {Event} e the event parameter from the handler
             * @return {Event} the event 
             * @static
             */
            getEvent: function(e) {
                var ev = e || window.event;

                if (!ev) {
                    var c = this.getEvent.caller;
                    while (c) {
                        ev = c.arguments[0];
                        if (ev && Event == ev.constructor) {
                            break;
                        }
                        c = c.caller;
                    }
                }

                return ev;
            },

            /**
             * Returns the charcode for an event
             * @method getCharCode
             * @param {Event} ev the event
             * @return {int} the event's charCode
             * @static
             */
            getCharCode: function(ev) {
                return ev.charCode || ev.keyCode || 0;
            },

            /**
             * Locating the saved event handler data by function ref
             *
             * @method _getCacheIndex
             * @static
             * @private
             */
            _getCacheIndex: function(el, sType, fn) {
                for (var i=0,len=listeners.length; i<len; ++i) {
                    var li = listeners[i];
                    if ( li                 && 
                         li[this.FN] == fn  && 
                         li[this.EL] == el  && 
                         li[this.TYPE] == sType ) {
                        return i;
                    }
                }

                return -1;
            },

            /**
             * Generates an unique ID for the element if it does not already 
             * have one.
             * @method generateId
             * @param el the element to create the id for
             * @return {string} the resulting id of the element
             * @static
             */
            generateId: function(el) {
                var id = el.id;

                if (!id) {
                    id = "yuievtautoid-" + counter;
                    ++counter;
                    el.id = id;
                }

                return id;
            },


            /**
             * We want to be able to use getElementsByTagName as a collection
             * to attach a group of events to.  Unfortunately, different 
             * browsers return different types of collections.  This function
             * tests to determine if the object is array-like.  It will also 
             * fail if the object is an array, but is empty.
             * @method _isValidCollection
             * @param o the object to test
             * @return {boolean} true if the object is array-like and populated
             * @static
             * @private
             */
            _isValidCollection: function(o) {
                return ( o                    && // o is something
                         o.length             && // o is indexed
                         typeof o != "string" && // o is not a string
                         !o.tagName           && // o is not an HTML element
                         !o.alert             && // o is not a window
                         typeof o[0] != "undefined" );

            },

            /**
             * @private
             * @property elCache
             * DOM element cache
             * @static
             */
            elCache: {},

            /**
             * We cache elements bound by id because when the unload event 
             * fires, we can no longer use document.getElementById
             * @method getEl
             * @static
             * @private
             */
            getEl: function(id) {
                return document.getElementById(id);
            },

            /**
             * Clears the element cache
             * @deprecated Elements are not cached any longer
             * @method clearCache
             * @static
             * @private
             */
            clearCache: function() { },

            /**
             * hook up any deferred listeners
             * @method _load
             * @static
             * @private
             */
            _load: function(e) {
                loadComplete = true;
                var EU = YAHOO.util.Event;
                // 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);
                }
            },

            /**
             * 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;
                }

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

                        if (el) {
                            // The element is available, but not necessarily ready
                            // @todo verify IE7 compatibility
                            // @todo should we test parentNode.nextSibling?
                            // @todo re-evaluate global content ready
                            if ( !item.checkReady || 
                                    loadComplete || 
                                    el.nextSibling ||
                                    (document && document.body) ) {

                                var scope = el;
                                if (item.override) {
                                    if (item.override === true) {
                                        scope = item.obj;
                                    } else {
                                        scope = item.override;
                                    }
                                }
                                item.fn.call(scope, item.obj);
                                //delete onAvailStack[i];
                                // null out instead of delete for Opera
                                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 elListeners = this.getListeners(el, sType);
                if (elListeners) {
                    for (var i=0,len=elListeners.length; i<len ; ++i) {
                        var l = elListeners[i];
                        // can't use the index on the changing collection
                        //this.removeListener(el, l.type, l.fn, l.index);
                        this.removeListener(el, l.type, l.fn);
                    }
                }

                if (recurse && el && el.childNodes) {
                    for (i=0,len=el.childNodes.length; i<len ; ++i) {
                        this.purgeElement(el.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} the element 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)  whether or not to adjust the default scope
             * &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];
                }

                for (var j=0;j<searchLists.length; ++j) {
                    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] === el && 
                                    (!sType || sType === l[this.TYPE]) ) {
                                results.push({
                                    type:   l[this.TYPE],
                                    fn:     l[this.FN],
                                    obj:    l[this.OBJ],
                                    adjust: 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;

                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.OBJ];
                            } else {