helper fn for console logging set $.fn.ajaxSubmit.debug to true to enable debug logging
function log() {
  if ($.fn.ajaxSubmit.debug) {
    var msg = '[jquery.form] ' + Array.prototype.join.call(arguments,'');
    if (window.console && window.console.log) {
      window.console.log(msg);
    }
    else if (window.opera && window.opera.postError) {
      window.opera.postError(msg);
    }
  }
}