用Dojo实现tab页的过程中，没有引用“on.js”，但是firebug调试时一直提示如下错误：
on.js源码如下：
define(["./has!dom-addeventlistener?:./aspect", "./_base/kernel", "./sniff"], function(aspect, dojo, has){
"use strict";
if(has("dom")){ // check to make sure we are in a browser, this module should work anywhere
var major = window.ScriptEngineMajorVersion;
has.add("jscript", major && (major() + ScriptEngineMinorVersion() / 10));
has.add("event-orientationchange", has("touch") && !has("android")); // TODO: how do we detect this?
has.add("event-stopimmediatepropagation", window.Event && !!window.Event.prototype && !!window.Event.prototype.stopImmediatePropagation);
has.add("event-focusin", function(global, doc, element){
return 'onfocusin' in element || (element.addEventListener && (function () {
var hasFocusInEvent = false;
function testFocus() {
hasFocusInEvent = true;
}
try {
var element = doc.createElement('input'),
activeElement = doc.activeElement;
element.style.position = 'fixed';
element.addEventListener('focusin', testFocus, false);
doc.body.appendChild(element);
element.focus();
doc.body.removeChild(element);
element.removeEventListener('focusin', testFocus, false);
activeElement.focus();
} catch (e) {}
return hasFocusInEvent;
})());
});
}
var on = function(target, type, listener, dontFix){
// summary:
// A function that provides core event listening functionality. With this function
// you can provide a target, event type, and listener to be notified of
// future matching events that are fired.
// target: Element|Object
// This is the target object or DOM element that to receive events from
// type: String|Function
// This is the name of the event to listen for or an extension event type.
// listener: Function
// This is the function that should be called when the event fires.
// returns: Object
// An object with a remove() method that can be used to stop listening for this
// event.
// description:
// To listen for "click" events on a button node, we can do:
// | define(["dojo/on"], function(listen){
// | on(button, "click", clickHandler);
// | ...
// Evented JavaScript objects can also have their own events.
// | var obj = new Evented;
// | on(obj, "foo", fooHandler);
// And then we could publish a "foo" event:
// | on.emit(obj, "foo", {key: "value"});
// We can use extension events as well. For example, you could listen for a tap gesture:
// | define(["dojo/on", "dojo/gesture/tap", function(listen, tap){
// | on(button, tap, tapHandler);
// | ...
// which would trigger fooHandler. Note that for a simple object this is equivalent to calling:
// | obj.onfoo({key:"value"});
// If you use on.emit on a DOM node, it will use native event dispatching when possible.
if(typeof target.on == "function" && typeof type != "function" && !target.nodeType){
// delegate to the target's on() method, so it can handle it's own listening if it wants (unless it
// is DOM node and we may be dealing with jQuery or Prototype's incompatible addition to the
// Element prototype
return target.on(type, listener);
}
// delegate to main listener code
return on.parse(target, type, listener, addListener, dontFix, this);
};
on.pausable = function(target, type, listener, dontFix){
// summary:
// This function acts the same as on(), but with pausable functionality. The
// returned signal object has pause() and resume() functions. Calling the
// pause() method will cause the listener to not be called for future events. Calling the
// resume() method will cause the listener to again be called for future events.
var paused;
var signal = on(target, type, function(){
if(!paused){
return listener.apply(this, arguments);
}
}, dontFix);
signal.pause = function(){
paused = true;
};
signal.resume = function(){
paused = false;
};
return signal;
};
on.once = function(target, type, listener, dontFix){
// summary:
// This function acts the same as on(), but will only call the listener once. The
// listener will be called for the first
// event that takes place and then listener will automatically be removed.
var signal = on(target, type, function(){
// remove this listener
signal.remove();
// proceed to call the listener
return listener.apply(this, arguments);
});
return signal;
};
on.parse = function(target, type, listener, addListener, dontFix, matchesTarget){
if(type.call){
// event handler function
// on(node, touch.press, touchListener);
return type.call(matchesTarget, target, listener);
}
if(type.indexOf(",") > -1){
// we allow comma delimited event names, so you can register for multiple events at once
var events = type.split(/\s*,\s*/);
var handles = [];
var i = 0;
var eventName;
while(eventName = events[i++]){
handles.push(addListener(target, eventName, listener, dontFix, matchesTarget));
}
handles.remove = function(){
for(var i = 0; i < handles.length; i++){
handles[i].remove();
}
};
return handles;
}
return addListener(target, type, listener, dontFix, matchesTarget);
};
var touchEvents = /^touch/;
function addListener(target, type, listener, dontFix, matchesTarget){
// event delegation:
var selector = type.match(/(.*):(.*)/);
// if we have a selector:event, the last one is interpreted as an event, and we use event delegation
if(selector){
type = selector[2];
selector = selector[1];
// create the extension event for selectors and directly call it
return on.selector(selector, type).call(matchesTarget, target, listener);
}
// test to see if it a touch event right now, so we don't have to do it every time it fires
if(has("touch")){
if(touchEvents.test(type)){
// touch event, fix it
listener = fixTouchListener(listener);
}
if(!has("event-orientationchange") && (type == "orientationchange")){
//"orientationchange" not supported <= Android 2.1,
//but works through "resize" on window
type = "resize";
target = window;
listener = fixTouchListener(listener);
}
}
if(addStopImmediate){
// add stopImmediatePropagation if it doesn't exist
listener = addStopImmediate(listener);
}
// normal path, the target is |this|
if(target.addEventListener){
// the target has addEventListener, which should be used if available (might or might not be a node, non-nodes can implement this method as well)
// check for capture conversions
var capture = type in captures,
adjustedType = capture ? captures[type] : type;
target.addEventListener(adjustedType, listener, capture);
// create and return the signal
return {
remove: function(){
target.removeEventListener(adjustedType, listener, capture);
}
};
}
type = "on" + type;
if(fixAttach && target.attachEvent){
return fixAttach(target, type, listener);
}
throw new Error("Target must be an event emitter");
}
on.selector = function(selector, eventType, children){
// summary:
// Creates a new extension event with event delegation. This is based on
// the provided event type (can be extension event) that
// only calls the listener when the CSS selector matches the target of the event.
//
// The application must require() an appropriate level of dojo/query to handle the selector.
// selector:
// The CSS selector to use for filter events and determine the |this| of the event listener.
// eventType:
// The event to listen for
// children:
// Indicates if children elements of the selector should be allowed. This defaults to
// true
// example:
// | require(["dojo/on", "dojo/mouse", "dojo/query!css2"], function(listen, mouse){
// | on(node, on.selector(".my-class", mouse.enter), handlerForMyHover);
return function(target, listener){
// if the selector is function, use it to select the node, otherwise use the matches method
var matchesTarget = typeof selector == "function" ? {matches: selector} : this,
bubble = eventType.bubble;
function select(eventTarget){
// see if we have a valid matchesTarget or default to dojo/query
matchesTarget = matchesTarget && matchesTarget.matches ? matchesTarget : dojo.query;
// there is a selector, so make sure it matches
while(!matchesTarget.matches(eventTarget, selector, target)){
if(eventTarget == target || children === false || !(eventTarget = eventTarget.parentNode) || eventTarget.nodeType != 1){ // intentional assignment
return;
}
}
return eventTarget;
}
if(bubble){
// the event type doesn't naturally bubble, but has a bubbling form, use that, and give it the selector so it can perform the select itself
return on(target, bubble(select), listener);
}
// standard event delegation
return on(target, eventType, function(event){
// call select to see if we match
var eventTarget = select(event.target);
// if it matches we call the listener
return eventTarget && listener.call(eventTarget, event);
});
};
};
function syntheticPreventDefault(){
this.cancelable = false;
this.defaultPrevented = true;
}
function syntheticStopPropagation(){
this.bubbles = false;
}
var slice = [].slice,
syntheticDispatch = on.emit = function(target, type, event){
// summary:
// Fires an event on the target object.
// target:
// The target object to fire the event on. This can be a DOM element or a plain
// JS object. If the target is a DOM element, native event emitting mechanisms
// are used when possible.
// type:
// The event type name. You can emulate standard native events like "click" and
// "mouseover" or create custom events like "open" or "finish".
// event:
// An object that provides the properties for the event. See https://developer.mozilla.org/en/DOM/event.initEvent
// for some of the properties. These properties are copied to the event object.
// Of particular importance are the cancelable and bubbles properties. The
// cancelable property indicates whether or not the event has a default action
// that can be cancelled. The event is cancelled by calling preventDefault() on
// the event object. The bubbles property indicates whether or not the
// event will bubble up the DOM tree. If bubbles is true, the event will be called
// on the target and then each parent successively until the top of the tree
// is reached or stopPropagation() is called. Both bubbles and cancelable
// default to false.
// returns:
// If the event is cancelable and the event is not cancelled,
// emit will return true. If the event is cancelable and the event is cancelled,
// emit will return false.
// details:
// Note that this is designed to emit events for listeners registered through
// dojo/on. It should actually work with any event listener except those
// added through IE's attachEvent (IE8 and below's non-W3C event emitting
// doesn't support custom event types). It should work with all events registered
// through dojo/on. Also note that the emit method does do any default
// action, it only returns a value to indicate if the default action should take
// place. For example, emitting a keypress event would not cause a character
// to appear in a textbox.
// example:
// To fire our own click event
// | require(["dojo/on", "dojo/dom"
// | ], function(on, dom){
// | on.emit(dom.byId("button"), "click", {
// | cancelable: true,
// | bubbles: true,
// | screenX: 33,
// | screenY: 44
// | });
// We can also fire our own custom events:
// | on.emit(dom.byId("slider"), "slide", {
// | cancelable: true,
// | bubbles: true,
// | direction: "left-to-right"
// | });
// | });
var args = slice.call(arguments, 2);
var method = "on" + type;
if("parentNode" in target){
// node (or node-like), create event controller methods
var newEvent = args[0] = {};
for(var i in event){
newEvent[i] = event[i];
}
newEvent.preventDefault = syntheticPreventDefault;
newEvent.stopPropagation = syntheticStopPropagation;
newEvent.target = target;
newEvent.type = type;
event = newEvent;
}
do{
// call any node which has a handler (note that ideally we would try/catch to simulate normal event propagation but that causes too much pain for debugging)
target[method] && target[method].apply(target, args);
// and then continue up the parent node chain if it is still bubbling (if started as bubbles and stopPropagation hasn't been called)
}while(event && event.bubbles && (target = target.parentNode));
return event && event.cancelable && event; // if it is still true (was cancelable and was cancelled), return the event to indicate default action should happen
};
var captures = has("event-focusin") ? {} : {focusin: "focus", focusout: "blur"};
if(!has("event-stopimmediatepropagation")){
var stopImmediatePropagation =function(){
this.immediatelyStopped = true;
this.modified = true; // mark it as modified so the event will be cached in IE
};
var addStopImmediate = function(listener){
return function(event){
if(!event.immediatelyStopped){// check to make sure it hasn't been stopped immediately
event.stopImmediatePropagation = stopImmediatePropagation;
return listener.apply(this, arguments);
}
};
}
}
if(has("dom-addeventlistener")){
// emitter that works with native event handling
on.emit = function(target, type, event){
if(target.dispatchEvent && document.createEvent){
// use the native event emitting mechanism if it is available on the target object
// create a generic event
// we could create branch into the different types of event constructors, but
// that would be a lot of extra code, with little benefit that I can see, seems
// best to use the generic constructor and copy properties over, making it
// easy to have events look like the ones created with specific initializers
var nativeEvent = target.ownerDocument.createEvent("HTMLEvents");
nativeEvent.initEvent(type, !!event.bubbles, !!event.cancelable);
不知道是什么原因