/*
  This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
  (see http://creativecommons.org/licenses/by-nc-sa/3.0)
*/

function $(v) {
  return(document.getElementById(v));
}

function $S(v) {
  return($(v).style);
}

function $F(f,v) {
  return($f(f).getElementById(v));
}

function $f(f) {
  return(frames[f].document);
}

function browser(v) {
  return(Math.max(navigator.userAgent.toLowerCase().indexOf(v),0));
}

var http_request = false;
function makeRequest(url, parameters, handler) {
  http_request = false;
  if(window.XMLHttpRequest) {
    http_request = new XMLHttpRequest();
  } else if(window.ActiveXObject) {
    try {
      http_request = new ActiveXObject("Microsoft.XMLHTTP");
    } catch(e) {}
  }
  if(!http_request) {
    alert('Cannot create XMLHTTP instance');
    return false;
  }
  http_request.onreadystatechange =
    function() {
      alertContents(handler);
    }
  http_request.open("GET", url + parameters, true);
  http_request.send(null);
}

function alertContents(handler) {
  if(http_request.readyState == 4) {
    if(http_request.status == 200) {
      var xmldoc = http_request.responseXML;
      var root = xmldoc.getElementsByTagName("root").item(0);
      handler.xmlAction(getNodeData(root));
    } else {
      alert("There was a problem with the request: " + http_request.status);
    }
  }
}

function getNodeData(parentNode) {
  if(parentNode.childNodes.length == 1 &&
     parentNode.childNodes.item(0).nodeName == "#text") {
    return parentNode.childNodes.item(0).nodeValue;
  }
  var xmldata = new Array();
  for(var i = 0; i < parentNode.childNodes.length; i++) {
    var childNode = parentNode.childNodes.item(i);
    xmldata[childNode.nodeName] = getNodeData(childNode);
  }
  return xmldata;
}