Moo.fx and Prototype

Is there any way to have prototype ajax do this:

function go() {
var url = './ajax.php';
var params = 'txt=' + $F('txt');
var ajax = new Ajax.Updater(
{success: 'lf'},
url,
{method: 'get', parameters: params, onLoading: showload, onFailure: reportError});
}
function reportError(request) {
 $F('lf') = "AJAX Error.";
}

and then do a moo.fx effect once it comes back?  Like the slide down one?

So it would be submitted and then the stuff that comes back will like be uncovered - i think you do it with fx.height but im not sure how to do this....

Thanks!

Sorry to get off topic slightly. Are there any good books on this advanced JavaScript?