How to check current user in particular group in JavaScript using SPServices

Add two JavaScript file in your Style Library.

1. Javascript 1.7.1.js (Download from here)

2. jquery.SPServices-0.7.1a.min.js (Download from here)

<script type="text/javascript" src="/Style%20Library/js/jquery-1.7.1.min.js"></script>
<script type="text/javascript" src="/Style%20Library/js/jquery.SPServices-0.7.1a.min.js"></script>
<script language="javascript" type="text/javascript">

$(document).ready(function () {        
        $().SPServices({
            operation: "GetGroupCollectionFromUser",
            userLoginName: $().SPServices.SPGetCurrentUser(),
            async: false,
            completefunc: function (xData, Status) {
                if ($(xData.responseXML).find("Group[Name='SPGroup1']").length == 1) {
                    location.href = location.href.replace('/EditFormMKT.aspx', '/EditFormUW.aspx');
                }
                else if ($(xData.responseXML).find("Group[Name='SPGroup2']").length == 1) {
                    location.href = location.href.replace('/EditFormMKT.aspx', '/EditFormLegal.aspx');
                }
                else if ($(xData.responseXML).find("Group[Name='SPGroup3']").length == 1) {
                    location.href = location.href.replace('/EditFormMKT.aspx', '/EditFormDesigner.aspx');
                }
                else if ($(xData.responseXML).find("Group[Name='SPGroup4']").length == 1) {
                    location.href = location.href.replace('/EditFormMKT.aspx', '/EditFormRequester.aspx');
                }
            }
        });
    });
</script>

Group1, Group2 and Group3 etc are SharePoint Groups. Replace your group name with this group name and what ever you want to do write your code below of it.

Here I am replacing the URL and redirect the user based on his role. You can also call particular JavaScript function based on user's group.

Hope this is helpful to you.