readme

这是YUI的源码及相关示例。里面有很多很炫的Javascript效果。

+ Tuned scrolling behavior so that when the user has scrolled to the bottom of 
  a YAHOO.widget.Menu instance and starts pressing the up arrow key, the 
  contents begin scrolling only when the next item to be selected is out of 
  view of the scrollable area.

+ Modified "removeMenu" method of YAHOO.widget.MenuManager so that it removes
  the specified YAHOO.widget.Menu instance from the collection of visible menus.
 
+ Calling the "destroy" method of a visible YAHOO.widget.Menu instance now
  purges it from the YAHOO.widget.Manager's collection of visible Menus.
 
+ YAHOO.widget.Menu instances now blur before hiding.

+ The debug version of YAHOO.widget.Menu now correctly logs as "Menu" rather 
  than "Overlay" in IE.
  
+ Setting a YAHOO.widget.MenuItem instance's "checked" configuration property 
  to "true" two or more times followed by "false" will no longer result in some 
  of the DOM elements used to render the checkmark icon will no longer remain 
  in the item's DOM.

+ It is now possible to click anywhere on a YAHOO.widget.MenuItem instance 
  and have it navigate to the URL specified by its "url" configuration property 
  - even if the MenuItem has a value specified for its "target"
  configuation property.

+ The "toString" method of YAHOO.widget.MenuItem now returns the instance's id.

+ Setting the YAHOO.widget.MenuItem.prototype.COLLAPSED_SUBMENU_INDICATOR_TEXT 
  constant to empty string no longer results in JavaScript error.

+ YAHOO.widget.MenuBar instances behave the same regardless of the value
  of their "position" configuration property.

+ It is now possible to ctr or shift-click on YAHOO.widget.MenuItem instances 
  without the browser automatically redirecting to the URL specified by the 
  MenuItem's "url" configuration property.


Added the following features:
-----------------------------

+ Prototype of all classes (Menu, ContextMenu, MenuBar, MenuItem, 
  ContextMenuItem, MenuBarItem) are augmented with YAHOO.util.EventProvider.

+ Added the following methods to YAHOO.widget.MenuManager:

    - "getMenuItem"
    - "getMenuItemGroup"

+ Added the following methods to YAHOO.widget.Menu:

    - "subscribe" 
    - "getSubmenus"
    - "onRender"

+ Added a "disabled" configuration property to YAHOO.widget.Menu.

+ Added the constant "CSS_LABEL_CLASS_NAME" to YAHOO.widget.MenuItem that 
  represents the name of the CSS class applied to the <A/> node that is the 
  first child of its root <LI/> node.

+ Added the constant "CSS_LABEL_CLASS_NAME" to YAHOO.widget.MenuBarItem that 
  represents the name of the CSS class applied to the <A/> node that is the 
  first child of its root <LI/> node.

+ Added ability for YAHOO.widget.Menu instances to have shadow:

    - The shadow for a Menu is implemented by appending a new element as the 
      last child of its root <DIV/> element:

        <DIV class="yuimenu">
            <DIV class="bd">
                <UL>
                    <LI class="yuimenuitem"/>
                    <LI class="yuimenuitem"/>
                    <LI class="yuimenuitem"/>
                </UL>
            </DIV>
            <DIV class="yui-menu-shadow"/>
        </DIV>

    - The code that creates the shadow element resides inside the Menu's 
      public "onRender" prototype method.  To disable the creation of a Menu's 
      shadow override the prototype of the "onRender" method:
      
      YAHOO.widget.Menu.prototype.onRender = function () { };
      
    - The actual creation of the shadow element is deferred until the Menu is 
      made visible for the first time.
      
    - The shadow element is only created for Menu instances whose
      "position" configuration property is set to "dynamic."

    - A Menu's shadow element can be styled via two CSS classes:

        + "yui-menu-shadow"  - Applied to the shadow element when it is created.
        + "yui-menu-shadow-visible" - Applied to the shadow element when the 
        Menu is visible; it is removed when hidden.

    - The shadow element is only styled when using the new "Sam" skin, for
      the previous default skin its "display" property is set to "none."


Changes:
--------

+ Deprecated "browser" property of YAHOO.widget.MenuItem in favor 
  of the YAHOO.env.ua.

+ Modified the DOM structure for a YAHOO.widget.MenuItem instance so that its
  root <LI/> node only has only two direct descendants: 
  
    - The <A/> node for its text label
    - The <DIV/> node for its submenu
  
  The submenu indicator node (<EM class="submenuindicator" />), checked 
  indicator node (<EM class="checkedindicator" />), and help text node
  (<EM class="helptext" />) that were previously direct descendants of a
  YAHOO.widget.MenuItem instance's root <LI/> are now direct descendants of 
  its <A/> node:

    <LI class="yuimenuitem || yuimenubaritem">

        <A class="yuimenuitemlabel || yuimenubaritemlabel">

            Text Label

            <EM class="helptext"> Help Text </EM>   (Optional)
            <EM class="checkedindicator"> ... </EM> (Optional)
            <EM class="submenuindicator"> ... </EM> (Optional)

        </A>

        <DIV class="yuimenu"> ... </DIV> (Optional submenu node)

    </LI>

+ As a result of the DOM structure changes for YAHOO.widget.MenuItem, the
  following CSS class are now only applied to a YAHOO.widget.MenuItem 
  instance's <A/> node:

    - "selected"
    - "disabled"
    - "checked"
    - "hashelptext"
    - "hassubmenu"

+ The "text" configuration property of YAHOO.widget.MenuItem now accepts a 
  string of HTML (previously only accepted plain text).

+ The "emphasis" and "strongemphasis" configuration properties of 
  YAHOO.widget.MenuItem are no longer interpreted when building from 
  existing markup.

+ All YAHOO.widget.MenuItem instances built from markup must have an <A> node 
  as the first child of its root <LI> node.

+ When building YAHOO.widget.MenuItem instances from existing markup, the value 
  of the "text" property is set to the innerHTML of the menu item's <A> node.

+ Deprecated the following YAHOO.widget.MenuItem configuration properties:

    - "strongemphasis"
    - "emphasis"
    - "helptext"


Known Issues
------------

+ ContextMenu works differently in Opera
  --------------------------------------
  Opera doesn't support the "contextmenu" DOM event used to trigger the display
  of YAHOO.widget.ContextMenu instances.  As a result, clicking the right mouse 
  button in Opera will not result in the display of a ContextMenu instance 
  as it would in IE, Gecko, and Safari.  To work around this shortcoming, users 
  will need to do the following to trigger the display of 
  YAHOO.widget.ContextMenu instances in Opera:

    - Opera for Windows: Hold down the control key while clicking with the 
      left mouse button.

    - Opera for Mac OS X: Hold down the command/Apple key while clicking with  
      the left mouse button.

+ Focus highlight sticks in Opera 
  -------------------------------
  In Opera focus is designated via the application of a background color 
  to an element's text node.  When a Menu instance has focus in Opera, the 
  focus highlight can remain on a MenuItem instance even after it has blurred.

+ ContextMenu instances cannot be invoked by clicking on Java Applets
  -------------------------------------------------------------------
  When a Java Applet is specified as the "trigger" element for a ContextMenu 
  instance it will not display when the Applet is clicked.  This is not a 
  bug in the ContextMenu class, but rather a result of DOM events not bubbling 
  up from inside Java Applets.  For more information on this issue see:
  http://tech.groups.yahoo.com/group/ydn-javascript/message/12128

+ Flash Movies appear on top of Menu instances
  --------------------------------------------
  Flash movies can appear on top of Menu instances in IE and Gecko-based
  browsers.  To fix this problem, set the "wmode" of the Flash movie to either
  "transparent" or "opaque" as indicated below: 

  Via the <object> tag:

    <object>
        <param name="wmode" value="opaque">
    </object>

    <object>
        <param name="wmode" value="transparent"> 
    </object>

  Via the <embed> tag:
    
    <embed wmode="transparent"> ... </embed>
    <embed wmode="opaque"> ... </embed>

    ** For more information see 
       http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_15523

+ Menu instances not rendered at correct z-index in IE
  -------------------------------------------------------
  In IE, when a Menu instance is rendered inside a relatively positioned 
  element the z-index of the Menu instance is now relative to its 
  relatively positioned parent element.  This is not a bug in the 
  Menu class, but rather a bug in IE where relatively positioned elements 
  establish a new stacking context for their child nodes.  To avoid this 
  bug is recommend that all Menu instances that need to be able to float
  above any other element in the document be made direct descendants of the 
  <body> element.
  
  ** For more information see 
   http://therealcrisp.xs4all.nl/meuk/IE-zindexbug.html

+ Elements with scrollbars poke through Menu instances floating above them
  ------------------------------------------------------------------------
  There is a bug in Gecko-based browsers for Mac OS X where an element's 
  scrollbars will poke through absolutely positioned elements floating above
  them.  To fix this problem the "overflow" property of a Menu instance's 
  shadow element is toggled between "hidden" and "auto" (through the application 
  and removal of the "hide-scrollbars" and "show-scrollbars" CSS classes) as its 
  "visibility" configuration property is toggled between "false" and "true."
  Therefore, the shadow element acts like a shim, blocking scrollbars from
  poking through the Menu.

  PLEASE NOTE:  

  1) The "hide-scrollbars" and "show-scrollbars" CSS classes classes are 
     applied only for Gecko on Mac OS X and are added/removed to/from the 
     Menu's root HTML element (DIV) via the "hideMacGeckoScrollbars" and 
     "showMacGeckoScrollbars" methods of YAHOO.widget.Overlay.  
  
  2) This fix is only applied when using the "Sam" skin; the CSS for the 
     original Menu skin does not contain any rules for rendering the 
     shadow element.  
  
  3) Once the fix is applied the bug will reappear if the window loses focus.  
     This can be fixed via Javascript by hiding and showing the Menu instance 
     when the window receives focus:

        YAHOO.util.Event.on(window, "focus", function () {
        
            oMyMenu.hide();
            oMyMenu.show();
        
        });

    ** For more information see 
       https://bugzilla.mozilla.org/show_bug.cgi?id=187435


*** version 2.2.2 ***

Fixed the following bugs:
-------------------------

+ "toString" method of MenuItem, MenuBarItem and ContextMenuItem classes will
  no longer throw a JavaScript error when using the debug version 
  of the Event utility.

+ "toString" method of Menu, MenuBar and ContextMenu classes will
  no longer attempt to output the instance's id if it is not available.

+ Logger statements output by debug version of MenuManager are now properly 
  categorized as "MenuManager"



*** version 2.2.1 ***

Added the following features:
-----------------------------

+ Added the following methods to YAHOO.widget.Menu:
  - "focus"
  - "blur"
  - "hasFocus"

+ Added the following Custom Events to YAHOO.widget.Menu:
    + "focusEvent"
    + "blurEvent"

+ Added the following methods to YAHOO.widget.MenuManager:
  - "getFocusedMenuItem"
  - "getFocusedMenu"

+ Added "hasFocus" method to YAHOO.widget.MenuItem


Fixed the following bugs:
-------------------------

+ Menu instances no longer set focus to themselves by default when made 
  visible.  Menus only receive focus in response to the following events: 
    - The user mouses down on a MenuItem instance
    - The user tabs into a MenuItem instance

+ Application of the "maxheight" configuration property is now correctly 
  deferred until the "render" event fires when Menu instance is being 
  lazy loaded.

+ The "maxheight" configuration property can now be set multiple times without 
  a Menu instance restoring itself to its original default height.

+ The "maxheight" configuration property can now be set on hidden Menu 
  instances that use lazy loading. 

+ Menu instances with a "width" configuration property set will now render 
  at the specified width rather than shrink wrapping to their contents.

+ Menu item help text no longer wraps to the next line in Opera 9.

+ Immediate submenus of a Menubar instance will no longer shift their position 
  to try and remain inside the confines of the browser's viewport.

+ Lazy loaded ContextMenu instances now appear in the correct position when 
  they are made visible for the first time.

+ MenuBar instances no longer throw JavaScript errors when navigating items with
  submenus containing no active items using the keyboard.

+ Replaced use of native "hasOwnProperty" method 
  with YAHOO.lang.hasOwnProperty.

+ Rendered Menu instances will now update their width when items are added 
  or removed.

+ Mousing over a Menu instance in an IE window that does not have focus will 
  no longer cause the window to receive focus.


Changes:
--------

+ "activeItem" property of YAHOO.widget.Menu now returns a reference to the 
  Menu's currently selected item.

+ Added a "visible" CSS class that is applied to visible Menu instances.

+ Refactored the Menu family to improve performance, especially when working 
  with a large number of instances in IE6.



*** version 2.2.0 ***

Added the following features:
-----------------------------

* Added two new methods to YAHOO.widget.Menu:

    * "getItems" - Returns a flat array of the items in a menu.