How to check Logged-In User in a SharePoint Group

<script type="text/javascript">

$( document ).ready(function() {

 var userName = $().SPServices.SPGetCurrentUser();

 $().SPServices({

 operation: "GetGroupCollectionFromUser", 

 userLoginName: userName,

 async: false,

 completefunc: function (xData, Status) { 

 if ($(xData.responseXML).find("Group[Name='Manager']").length == 1) {

     alert("Group user");

 }

 else {

      alert("login outside of the Group user");  

 }

 }

 });

});

</script>