var req;
var stopWindow = 0;

function loadXMLDoc(url) {
  if (window.XMLHttpRequest) {
    req = new XMLHttpRequest();
    req.onreadystatechange = processReqChange;
    req.open("GET", url, true);
    req.send(null);
  } else if (window.ActiveXObject) {
    req = new ActiveXObject("Microsoft.XMLHTTP");
    if (req) {
      req.onreadystatechange = processReqChange;
      req.open("GET", url, true);
      req.send();
    }
  }
}

function processReqChange() {
  if (req.readyState == 4) {
    if (req.status == 200) {
      eval(req.responseText);
    }
  }
}

function updateTowers(filter_att, filter_nextel, filter_sprint, filter_tmobile, filter_verizon) {
  var bounds = map.getBoundsLatLng();
  var url = "generate_towers.php?minx=" + bounds.minX + "&maxx=" + bounds.maxX + "&miny=" + bounds.minY + "&maxy=" + bounds.maxY + "&filter_att=" + filter_att + "&filter_nextel=" + filter_nextel + "&filter_sprint=" + filter_sprint + "&filter_tmobile=" + filter_tmobile + "&filter_verizon=" + filter_verizon;
  loadXMLDoc(url);
}

function createInfoWindow(marker, id, name, address, city, state) {
  stopWindow = 1;
  var html = "<h1><a href='http://www.cellreception.com/towers/details.php?id=" + id + "'>" + name + "</a></h1><br>" + address + "<br>" + city + ", " + state;

  marker.openInfoWindowHtml(html);
}