/* Class: Querystring
   Querystring([qs]): constructor (querystring used if qs missing)
      Querystring.get(key,default):   get value of parameter key (case-insensitive)
         Querystring.webstir():  automatic support for legacy webstir parameters
*/
function Querystring(qs) { // optionally pass a querystring to parse
  this.params = new Object();
  this.get=Querystring_get;

  if (qs == null)
    qs=location.search.substring(1,location.search.length);

  if (qs.length == 0) return;

  // Turn <plus> back to <space>
  // See: http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13.4.1
  qs = qs.replace(/\+/g, ' ');
  var args = qs.split('&'); // parse out name/value pairs separated via &

  // split out each name=value pair
  for (var i=0;i<args.length;i++) {
   var value;
   var pair = args[i].split('=');
   var name = unescape(pair[0]);

   if (pair.length == 2)
     value = unescape(pair[1]);
   else
     value = null;

   this.params[name.toLowerCase()] = value;
  }
}

function Querystring_get(key, default_) {
  // This silly looking line changes UNDEFINED to NULL
  if (default_ == null) default_ = null;

  var value=this.params[key.toLowerCase()];

  if (value==null) value=default_;

  return value;
}