rem: return false; 
add: return null; 
context: function testSessionHistory(webNav){  if (!webNav) {    alert("Didn't get web navigation object");    return false;  }   // Get the session history   getSHistory = webNav.sessionHistory;     return getSHistory;}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/e0e3a32c7d2e7f0e0d5fed54932a27821b36aa27/nsIWebNavTestLib.js/clean/embedding/qa/jstests/webNav/nsIWebNavTestLib.js