If you add:
jquery.form.min.js
You can simply do this:
<script>
$('#myform').ajaxForm(function(response) {
alert(response);
});
// this will register the AJAX for <form id="myform" action="some_url">
// and when you submit the form using <button type="submit"> or $('myform').submit(), then it will send your request and alert response
</script>
You could use simple $('FORM').serialize() as suggested in post above, but that will not work for FILE INPUTS... ajaxForm() will.