转：http://blog.csdn.net/lgm97/article/details/6409225

<!-- form digest  安全控件用来进行form的安全校验-->

<asp:ContentPlaceHolder id="PlaceHolderFormDigest" runat="server">

<SharePoint:FormDigest runat="server"/>

</asp:ContentPlaceHolder>

<!-- =====  隐藏的placeholder ============================================================ -->

<asp:Panel visible="false" runat="server">

<!-- =====  这些placeholder一般情况下不会输出任何东西 ========== -->

<!-- 在顶部导航栏中的导航菜单 -->

<asp:ContentPlaceHolder id="PlaceHolderHorizontalNav" runat="server"/>

<!-- The top navigation where GlobalNavigationSiteMap is contained. Gets overridden by default. V4 uses it to change the top nav -->

<asp:ContentPlaceHolder id="PlaceHolderTopNavBar" runat="server"/>

<!-- 快速导航的头 -->

<asp:ContentPlaceHolder id="PlaceHolderQuickLaunchTop" runat="server"/>

<!-- 快速导航的底. -->

<asp:ContentPlaceHolder id="PlaceHolderQuickLaunchBottom" runat="server"/>

<!--放置填入左导航的数据源 -->

<asp:ContentPlaceHolder id="PlaceHolderLeftNavBarDataSource" runat="server" />

<!-- 当页面上有日历时用到的时间选择器 -->

<asp:ContentPlaceHolder id="PlaceHolderCalendarNavigator" runat ="server" />

<!-- The top section of the left navigation bar. 左导航的顶部 -->

<asp:ContentPlaceHolder id="PlaceHolderLeftNavBarTop" runat="server" />

<!-- 用来override全局站点地图？-->

<asp:ContentPlaceHolder id="PlaceHolderGlobalNavigationSiteMap" runat="server" />

<!-- =====  这些placeholder并不以2010UI的部分出现，但必须出现以向后兼容
========== -->

<!--  当前页面所在的站点名 -->

<asp:ContentPlaceHolder id="PlaceHolderSiteName" runat="server"/>

<!-- 页面左上角的图标-->

<asp:ContentPlaceHolder ID="PlaceHolderPageImage" runat="server"/>

<!--标题区域的左边框 -->

<asp:ContentPlaceHolder ID="PlaceHolderTitleLeftBorder" runat="server"/>

<!-- mini console- supplementary buttons for pages like the wiki / history / incoming links -->

<asp:ContentPlaceHolder id="PlaceHolderMiniConsole" runat="server"/>

<!-- Right margin of the title area 标题区域的右边距 -->

<asp:ContentPlaceHolder id="PlaceHolderTitleRightMargin" runat="server"/>

<!-- 标题区域左侧的分隔区 -->

<asp:ContentPlaceHolder ID="PlaceHolderTitleAreaSeparator" runat="server"/>

<!-- 左导航区域的宽度-->

<asp:ContentPlaceHolder ID="PlaceHolderNavSpacer" runat="server"/>

<asp:ContentPlaceHolder id="PlaceHolderLeftNavBarBorder" runat="server"/>

<!-- 页面主体的边框元素 -->

<asp:ContentPlaceHolder ID="PlaceHolderBodyLeftBorder" runat="server"/>

<!--页面主体的右边距-->

<asp:ContentPlaceHolder id="PlaceHolderBodyRightMargin" runat="server" />

</asp:Panel>