function createRequestObject() {
  var req;
  if (window.XMLHttpRequest) { // Firefox, Safari, Opera...
    req = new XMLHttpRequest();
  } else if (window.ActiveXObject) { // Internet Explorer 5+
    req = new ActiveXObject("Microsoft.XMLHTTP");
  } else {
    // error creating the request object,
    // (maybe an old browser is being used?)
    alert('There was a problem creating the XMLHttpRequest object');
    req = '';
  }
  return req;
}

// Make the XMLHttpRequest object
var http = createRequestObject();

function sendRequest() {
  var now = new Date();
  http.open('get', 'scs/ajax/ant.cgi?aid=57&pid=11282&frq=30000&div=ajaxdiv1&nocache='+now.getTime());
  http.onreadystatechange = handleResponse;
  http.send(null);
}

function handleResponse() {
  if(http.readyState == 4 && http.status == 200){
    var response = http.responseText; // Text returned FROM perl script
    if(response) { // UPDATE ajaxTest content
      document.getElementById("ajaxdiv1").innerHTML = response;
      setTimeout('sendRequest()', 30000 ); // wait 30000 seconds, then do it all over again
    }
  }
}

sendRequest();