rem: var prefBranch = Components.classes["@mozilla.org/preferences-service;1"] .getService(Components.interfaces.nsIPrefBranch); 
add: var pref = document.getElementById("privacy.sanitize.promptOnSanitize"); 
context:   updateClearNowButtonLabel: function ()  {    var prefBranch = Components.classes["@mozilla.org/preferences-service;1"]                               .getService(Components.interfaces.nsIPrefBranch);    var clearNowButton = document.getElementById("clearDataNow");    if (prefBranch.getBoolPref("privacy.sanitize.promptOnSanitize"))      clearNowButton.label = clearNowButton.getAttribute("label1"); // "Clear Now..."    else      clearNowButton.label = clearNowButton.getAttribute("label2"); // "Clear Now"  },
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/77d4229c967c98f149bd4ac2844588cb93f6af0e/privacy.js/clean/browser/components/preferences/privacy.js