Firefox configuration for new tab

gistfile1.txt

// IMPORTANT: Start your code on the 2nd line

var {classes:Cc,interfaces:Ci,utils:Cu} = Components;
/* set new tab page */
try {
  Cu.import("resource:///modules/AboutNewTab.jsm");
  var newTabURL = "/Users/....startpages/index.html";
  AboutNewTab.newTabURL = newTabURL;
} catch(e){Cu.reportError(e);} // report errors in the Browser Console


// Auto focus new tab content
try {
  Cu.import("resource://gre/modules/Services.jsm");
  Cu.import("resource:///modules/BrowserWindowTracker.jsm");

  Services.obs.addObserver((event) => {
    window = BrowserWindowTracker.getTopWindow();
    window.gBrowser.selectedBrowser.focus();
  }, "browser-open-newtab-start");
} catch(e) { Cu.reportError(e); }