[danik.js]

В нормальных браузерах можно так сделать:

<script>
function sendForm(form, success) {
    var request = new XMLHttpRequest();
    request.open(form.method, form.action);
    request.onreadystatechange = function() {
        if (request.readyState == request.DONE) {
            if (request.code == 200) {
                success(request.responseText);
            }
        }
    };
    request.send(new FormData(form));
}
</script>
<form onsubmit="return sendForm(this, alert), false" action....>