function updatelinks(lon,lat,zoom) {
  var links = new Array();
  links['viewanchor'] = '/index.html';
  //links['editanchor'] = 'edit.html';
  links['uploadanchor'] = '/traces';
  links['loginanchor'] = '/login.html';
  links['logoutanchor'] = '/logout.html';
  links['registeranchor'] = '/create-account.html';

  var node;
  var anchor;
  for (anchor in links) {
    node = document.getElementById(anchor);
    if (! node) { continue; }
    var args = getArgs(node.href);
    args["lat"] = lat;
    args["lon"] = lon;
    args["zoom"] = zoom;
    node.href = setArgs(node.href, args);
  }

  node = document.getElementById("editanchor");
  if (node) {
    if ( zoom >= 14) {
      var args = getArgs(node.href);
      args.lat = lat;
      args.lon = lon;
      args.zoom = zoom;
      node.href = setArgs(node.href, args);
      node.style.fontStyle = 'normal';
    } else {
      node.href = 'javascript:alert("zoom in to edit map");';
      node.style.fontStyle = 'italic';
    }
  }
}

function getArgs(url) {
  var args = new Object();
  var querystart = url.indexOf("?");

  if (querystart >= 0) {
     var querystring = url.substring(querystart + 1);
     var queryitems = querystring.split("&");

     for (var i = 0; i < queryitems.length; i++) {
        if (match = queryitems[i].match(/^(.*)=(.*)$/)) {
           args[unescape(match[1])] = unescape(match[2]);
        } else {
           args[unescape(queryitems[i])] = null
        }
     }
  }

  return args;
}

function setArgs(url, args) {
   var queryitems = new Array();

   for (arg in args)
   {
      if (args[arg] == null) {
         queryitems.push(escape(arg));
      } else {
         queryitems.push(escape(arg) + "=" + escape(args[arg]));
      }
   }

   return url.replace(/\?.*$/, "") + "?" + queryitems.join("&");
}