rem: var prefs = Components.classes["@mozilla.org/preferences;1"].getService(Components.interfaces.nsIPref); var url = prefs.getDefaultLocalizedUnicharPref("mailnews.start_page.url"); 
add: var prefService = Components.classes["@mozilla.org/preferences-service;1"] .getService(Components.interfaces.nsIPrefService); var prefs = prefService.getDefaultBranch(null); var url = prefs.getComplexValue("mailnews.start_page.url", Components.interfaces.nsIPrefLocalizedString); 
context: function setHomePageToDefaultPage(folderFieldId){  var homePageField = document.getElementById(folderFieldId);  var prefs = Components.classes["@mozilla.org/preferences;1"].getService(Components.interfaces.nsIPref);  var url = prefs.getDefaultLocalizedUnicharPref("mailnews.start_page.url");  homePageField.value = url;}
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/faf03ce445712b372523f881cc3144cfadc7a611/pref-mailnews.js/clean/mailnews/base/prefs/resources/content/pref-mailnews.js