var cgiParams;

function parseCgiParams() {
  if (cgiParams) return;
  cgiParams = {};
  var search = String(document.location.search);
  if (!search) return;
  search = search.replace(/^\?/,''); 
  var pairs = search.split(/&/);
  for (var i=0; i<pairs.length; i++) {
    var part = pairs[i].split(/=/);
    cgiParams[part[0]] = part[1];
  }
}

function param(key) {
  if (!cgiParams) parseCgiParams();
  return cgiParams[key];
}

/**
 * Does an ajax call.  <code>f</code> takes an XML document and does
 * shit to it.
 */
function ajax(url,params,f) {
  return new Ajax.Request
    (url,
     { method: 'get',
         parameters: params,
         onSuccess:  function(r) {f(r.responseXML);},
         onError:    function(e) {alert(e);}
     });
}