rem: var urlBarHist = nsJSComponentManager.getService("component: 
add: var urlBarHist = nsJSComponentManager.getService("@mozilla.org/browser/urlbarhistory;1", 
context: function prefClearUrlbarHistory(){  var button = document.getElementById("ClearUrlBarHistoryButton");  var urlBarHist = nsJSComponentManager.getService("component://netscape/browser/urlbarhistory",  "nsIUrlbarHistory");  if ( urlBarHist )  {  	urlBarHist.clearHistory();  	dump("Now history should be empty. \n");    button.setAttribute("disabled","true");  }}  
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/0257791053c2b38e1dfaf2ee11afae973e82e394/prefutilities.js/clean/xpfe/components/prefwindow/resources/content/prefutilities.js