rem: var pings = elem.ping.split(" "); 
add: var pings = elem.ping; if (!pings) return result; pings = pings.split(" "); 
context: function getPings(elem){  var result = [];  var enabled = prefs.getBoolPref(PREF_PINGS_ENABLED);  if (!enabled)    return result;  var maxPings = prefs.getIntPref(PREF_PINGS_MAX_PER_LINK);  if (maxPings == 0)    return result;  var requireSameHost = prefs.getBoolPref(PREF_PINGS_REQUIRE_SAME_HOST);  const ios =      Components.classes["@mozilla.org/network/io-service;1"].      getService(Components.interfaces.nsIIOService);  var doc = elem.ownerDocument;  var docURI = ios.newURI(doc.documentURI, doc.characterSet, null);  // The URL strings returned by elem.ping are absolute URLs.  var pings = elem.ping.split(" ");  for (var i = 0; i < pings.length; ++i) {    if (requireSameHost) {      var uri = ios.newURI(pings[i], doc.characterSet, null);      if (uri.asciiHost == docURI.asciiHost)        result.push(pings[i]);    } else {      result.push(pings[i]);    }    if (result.length == maxPings)      break;  }  return result;}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/10234/97dd03bb54a93b46ab7744daddc4e9bc07760e2b/metaData.js/clean/browser/base/content/metaData.js