For the purpose of testing (and making this question simpler) I have been using xajax to output a random number into a DIV on the page.
$output=rand(20,40);
$ajax_resp->assign('container','innerHTML', $output);
After the DIV container is loaded, I also load 1 line of Javascript to call the xajax function.
<div id="container"></div>
<script type="text/javascript">
xajax_refresh().periodical(2000);
</script>
As you can see, I'm using the MooTools function called periodical() to call the function again after x milleseconds. It calls the function fine at first, but not again.
It doesn't automatically refresh. Why?
You are not assigning a periodical to xajax_refresh function, you are calling that function (with xajax_refresh()). For instance, you're assigning its returned value to periodical (It can be everything, but nothing happens because that returned value is not a function :) ).
Therefore, the solution is this:
<script type="text/javascript">
xajax_refresh.periodical(2000);
</script>