Hide Ribbon With Users Permissions

Ribbon is a great new feature introduced by SharePoint 2010.It provides many actions for different users,but sometimes,we don't want to see it.So I'll introduce how to hide the ribbon for users with different privileges in the following paragraph.

First,open the site by SharePoint Designer,find v4.master file and check it out,and edit it in advanced mode.

Then,find the following code in v4.master:

<div id="s4-ribbonrow" class="s4-pr s4-ribbonrowhidetitle">

Change the code to this one:

<div id="s4-ribbonrow" class="s4-pr s4-ribbonrowhidetitle" style="display:none">

And now,go to the end of this "div"(id="s4-ribbonrow") tag,add the following code after it:

<Sharepoint:SPSecurityTrimmedControl runat="server" PermissionsString="The Permissions Your Want To Set">
    <script type="text/javascript">
        document.getElementById("s4-ribbonrow").style.display = "block";
    </script>
</Sharepoint:SPSecurityTrimmedControl>

About the "PermissionsString" property,please refer to the following table,you can add one or more permissions to this property,just use "," to split them:

PermissionsString	Description
EmptyMask	Has no   permissions on the Web site. Not available through the user interface.
ViewListItems	View   items in lists, documents in document libraries, and view Web discussion   comments.
AddListItems	Add   items to lists, add documents to document libraries, and add Web discussion   comments.
EditListItems	Edit   items in lists, edit documents in document libraries, edit Web discussion   comments in documents, and customize Web Part Pages in document libraries.
DeleteListItems	Delete   items from a list, documents from a document library, and Web discussion   comments in documents.
ApproveItems	Approve   a minor version of a list item or document.
OpenItems	View   the source of documents with server-side file handlers.
ViewVersions	View   past versions of a list item or document.
DeleteVersions	Delete   past versions of a list item or document.
CancelCheckout	Discard   or check in a document which is checked out to another user.
ManagePersonalViews	Create,   change, and delete personal views of lists.
ManageLists	Create   and delete lists, add or remove columns in a list, and add or remove public   views of a list.
ViewFormPages	View   forms, views, and application pages, and enumerate lists.
Open	Allow   users to open a Web site, list, or folder to access items inside that   container.
ViewPages	View   pages in a Web site.
AddAndCustomizePages	Add,   change, or delete HTML pages or Web Part Pages, and edit the Web site using a   SharePoint Foundation–compatible editor.
ApplyThemeAndBorder	Apply   a theme or borders to the entire Web site.
ApplyStyleSheets	Apply   a style sheet (.css file) to the Web site.
ViewUsageData	View   reports on Web site usage.
CreateSSCSite	Create   a Web site using Self-Service Site Creation.
ManageSubwebs	Create   subsites such as team sites, Meeting Workspace sites, and Document Workspace   sites.
CreateGroups	Create   a group of users that can be used anywhere within the site collection.
ManagePermissions	Create   and change permission levels on the Web site and assign permissions to users   and groups.
BrowseDirectories	Enumerate   files and folders in a Web site using Microsoft Office SharePoint Designer   2007 and WebDAV interfaces.
BrowseUserInfo	View   information about users of the Web site.
AddDelPrivateWebParts	Add   or remove personal Web Parts on a Web Part Page.
UpdatePersonalWebParts	Update   Web Parts to display personalized information.
ManageWeb	Grant   the ability to perform all administration tasks for the Web site as well as   manage content. Activate, deactivate, or edit properties of Web site scoped   Features through the object model or through the user interface (UI). When   granted on the root Web site of a site collection, activate, deactivate, or   edit properties of site collection scoped Features through the object model.   To browse to the Site Collection Features page and activate or deactivate site collection scoped   Features through the UI, you must be a site collection administrator.
UseClientIntegration	Use   features that launch client applications; otherwise, users must work on   documents locally and upload changes.
UseRemoteAPIs	Use   SOAP, WebDAV, or Microsoft Office SharePoint Designer 2007 interfaces to   access the Web site.
ManageAlerts	Manage   alerts for all users of the Web site.
CreateAlerts	Create   e-mail alerts.
EditMyUserInfo	Allows   a user to change his or her user information, such as adding a picture.
EnumeratePermissions	Enumerate   permissions on the Web site, list, folder, document, or list item.
FullMask	Has   all permissions on the Web site. Not available through the user interface.

At last,save the v4.master and publish it.
References:SPBasePermissions Enumeration

                 How To Hide Ribbon From Users Without Edit Page Privilege