add: if (!gURLBar.value) return;  
context: function handleURLBarCommand(aTriggeringEvent) {  var postData = { };  canonizeUrl(aTriggeringEvent, postData);  try {    addToUrlbarHistory(gURLBar.value);  } catch (ex) {    // Things may go wrong when adding url to session history,    // but don't let that interfere with the loading of the url.  }  BrowserLoadURL(aTriggeringEvent, postData.value);}
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/480e437415520e786ea6265466a8ff4fb9f3287a/browser.js/clean/browser/base/content/browser.js