How to hide show Tab's based on User Roles in MS CRM 2011

Use the below lines of code to achieve your goal.

function OnLoad() {
if (UserHasRole("Customer Service") || UserHasRole("Service Manager")) {
Xrm.Page.ui.tabs.get('details').setVisible(false);
} else {
Xrm.Page.ui.tabs.get('details').setVisible(true);
}
}


function UserHasRole(roleName) {
var serverUrl = Xrm.Page.context.getServerUrl();
var oDataEndpointUrl = serverUrl + "/XRMServices/2011/OrganizationData.svc/";

var org = Xrm.Page.context.getOrgUniqueName()
var oDataEndpointUrl = "/" + org + "/XRMServices/2011/OrganizationData.svc/";

oDataEndpointUrl += "RoleSet?$top=1&$filter=Name eq '" + roleName + "'";

var service = GetRequestObject();

if (service != null) {
service.open("GET", oDataEndpointUrl, false);
service.setRequestHeader("X-Requested-Width", "XMLHttpRequest");
service.setRequestHeader("Accept", "application/json, text/javascript, */*");
service.send(null);

var requestResults = eval('(' + service.responseText + ')').d;

if (requestResults != null && requestResults.results.length == 1) {
var role = requestResults.results[0];

var id = role.RoleId;

var currentUserRoles = Xrm.Page.context.getUserRoles();

for (var i = 0; i < currentUserRoles.length; i++) {
var userRole = currentUserRoles[i];
if (GuidsAreEqual(userRole, id)) {
return true;
}
}
}
}

return false;
}

function GetRequestObject() {
if (window.XMLHttpRequest) {
return new window.XMLHttpRequest;
} else {
try {
return new ActiveXObject("MSXML2.XMLHTTP.3.0");
} catch (ex) {
return null;
}
}
}

function GuidsAreEqual(guid1, guid2) {
var isEqual = false;

if (guid1 == null || guid2 == null) {
isEqual = false;
} else {
isEqual = guid1.replace(/[{}]/g, "").toLowerCase() == guid2.replace(/[{}]/g, "").toLowerCase();
}

return isEqual;
}