<%=
    link_to('refresh', '/mycontroller/index', :remote => true)
%>

<div id="mydiv">
    <%=
        @mydata
    %>
</div>

$('#mydiv').html('<%= escape_javascript(@mydata) %>')

function executeQuery() {
  $.ajax({
    //url: '/index',
    success: function(data) {
      $('#mydiv').html(data)
    }
  });
  setTimeout(executeQuery, 500);
}

$(document).ready(function() {
  setTimeout(executeQuery, 500);
});

$('#mydiv').html(data)

$('#mydiv').load('/mycontroller/index #mydiv')

def action1
   <your code here>
end
def action2
   <your code here>
   render :layout => false
end