Listing 5. The JavaScript Component

function start_cid () {

  setInterval("update_cid()", 1000);
}

function update_cid () {
  var req;
  var xml;
  var panels;
  var count;
  var name;
  var div;

  req = get_from_server();

  clear_panels();

  xml = req.responseXML.getElementsByTagName("panels")[0];

  panels = xml.getElementsByTagName("panel");

  for (count=0 ; count < panels.length ; count++) {
    panel = panels[count];

    name = panel.getElementsByTagName("name")[0];
    name = name.firstChild.nodeValue;

    content = panel.getElementsByTagName("content")[0];
    content = content.firstChild.nodeValue;

    div = document.getElementById(name);

    div.style.display="block";
    div.innerHTML = "<b>" + name + ": </b>" + content;

    if (div.innerHTML == "") {
      div.style.display="none";
    }
  }
}

function get_from_server () {
  var req;

  if (window.XMLHttpRequest) {
    req = new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    req = new ActiveXObject("Microsoft.XMLHTTP");
  }

  req.open("GET", "/cgi-bin/cid.pl", false);
  req.send(null);

  return req;
}

function clear_panels () {
  for (count=1 ; count < 5 ; count++) {
    document.getElementById("phone" + count).innerHTML = "";
    document.getElementById("phone" + count).style.display="none";
  }

  return;
}