Return data after ajax call success

Return data after ajax call success

Hi everone how can I return data after ajax call success. I try to do it using async: false, but my browser is frozen.

I wan to do something like this 

function ajaxtest()
{
      var ActChatDepartmentArray = new Object();

    $.ajax({
          url: 'ajax/boldjsonfilewithoneparam/',
          type: 'POST',
          async: false,
          headers: { "X-CSRFToken": '{{csrf_token}}' },
          data: {
            'DepartmentID': DepartmentID,
            'paramString': "DepartmentID",
            'operations': "getActiveChats"
          },
          dataType: 'json',
          success: function (response) {
            $.each(response.Data, function(key, value){
                ActChatDepartmentArray[value.OperatorID] = { OperatorID: value.OperatorID, ChatID: value.ChatID};
            });
          },
          error: function (jqXhr, textStatus, errorMessage) { // error callback
                alert('Error: ' + errorMessage);
          },
                complete : function(jqXHR, textStatus){
         }
    });

    return ActChatDepartmentArray;;
}

then I want to be able to call my function as:

var i = ajaxtest();

Best regard,