new Ajax.Request("redirect.jsp", {
    on302:  function(response) {
        log("Got 302 response.");
    },
    onSuccess: function(response) {
        log("Got success, code = " + response.status);
        $('target').update(response.responseText);
    },
    onFailure: function(response) {
        log("Got failure, code = " + response.status);
    },
    onComplete: function(response) {
        log("Got completion, code = " + response.status);
    }
});