jQuery ping

/*
 * jQuery ping
 * Original code: http://ha.ckers.org/weird/xhr-ping-sweep.html
 */
<script type="text/javascript" src="./jquery-1.4.3.min.js"></script>
<script type="text/javascript" src="./timer.js"></script>

<script type="text/javascript">

url = "http://twitter.com/";

function log(data) { 
  var text;
  text = document.createElement('div');
  text.innerHTML = data + "<br>";
  document.body.appendChild(text);
}

function ping(url) {
  var d = new Date();
  $.ajax({
    type: "GET",
    url: url,
    cache: false,
    timeout: 60000,
    success: function(html, status, req) {
      var d2 = new Date();
      var time = d2.getTime() - d.getTime();
      if (req.status == 200 && time < 18000) {
        if (time > 10) {
          $("#rtt").html(time + "ms.");
        }
      } else {
        log("error! status: " + req.status);
      }
    },
    error: function(req, status, error) {
      log("error! status: " + req.status + " error: " + error);
    }
  });
}

$(function() {
  $("#url").html(url);
  $.timer(5000,function(timer) {
    ping(url);
  });
})
</script>

<table border="0">
<tr><td id="url"></td><td>:</td><td id="rtt"></td></tr>
</table>