ajax jquery return没有返回值

function editdivisionmember(division_id,users_id){
    $.ajax({
            type:"POST",
            url:"/default/index/ajax/do/editdivisionmember",
            data:"division_id="+division_id+"&users_id="+users_id,
            success:function(response){
                return response;
            }
        });
}

function deldivisionmember(divisionmember_id){
    $.ajax({
            type:"POST",
            async:false, 
            url:"/default/index/ajax/do/deldivisionmember",
            data:"divisionmember_id="+divisionmember_id,
            success:function(response){
                 res = response;
            }
        });
    return res;
}