New Post: Return value from GetListItems

Hi. I've been looking at this for days now and just can not get it to work. I'm trying to return value "email" outside the function call to a variable called "subEmail". Code is below. Any ideas? The alert does not work.

    var subEmail = getSubmitterEmail($userName);
    alert(subEmail);

    function getSubmitterEmail(userName) {
        
        var _query = "<Query><Where><Eq><FieldRef Name='firstLastName' /><Value Type='Text'>" + userName + "</Value></Eq></Where></Query>";

        $().SPServices({
            operation: 'GetListItems',
            async: false,
            webUrl: '/',
            listName: '{732DBD98-D0CF-4F7D-8281-4F9D419138D2}',
            CAMLViewFields: "<ViewFields><FieldRef Name='Email' /></ViewFields>",
            CAMLQuery: _query,
            completefunc: 
                function (xData, Status) {        
                    $(xData.responseXML).SPFilterNode("z:row").each(function() { 
                        var email = ($(this).attr("ows_Email"));
                        var isMatch = email.substr(0, 7) == "mailto:";
                        
                        if (isMatch = "true") {
                            email = email.substring(7); }
                    });             
                } //close completefunc
        }); //close SPServices  
        
        return email;
    };
});