rem: return getBrowser().webNavigation; 
add: return gBrowser.webNavigation; 
context: function getWebNavigation(){  try {    return getBrowser().webNavigation;  } catch (e) {    return null;  }}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/9a90fd69329163919e8e93ba3d72a613528d60dd/browser.js/clean/browser/base/content/browser.js