add:  var aFile = Components.classes["@mozilla.org/file/local;1"].createInstance(Components.interfaces.nsILocalFile); if (!aFile) return; aFile.initWithPath(fileName); if (!aFile.exists()) { aFile.create(Components.interfaces.nsIFile.NORMAL_FILE_TYPE, 0644); } 
context:   exportBookmarks: function ()  {    try {      const kFilePickerContractID = "@mozilla.org/filepicker;1";      const kFilePickerIID = Components.interfaces.nsIFilePicker;      const kFilePicker = Components.classes[kFilePickerContractID].createInstance(kFilePickerIID);            const kTitle = BookmarksUtils.getLocaleString("EnterExport");      kFilePicker.init(window, kTitle, kFilePickerIID["modeSave"]);      kFilePicker.appendFilters(kFilePickerIID.filterHTML | kFilePickerIID.filterAll);      kFilePicker.defaultString = "bookmarks.html";      var fileName;      if (kFilePicker.show() != kFilePickerIID.returnCancel) {        fileName = kFilePicker.file.path;        if (!fileName) return;      }      else return;    }    catch (e) {      return;    }    var selection = RDF.GetResource("NC:BookmarksRoot");    var args = [{ property: NC_NS+"URL", literal: fileName}];    this.doBookmarksCommand(selection, NC_NS_CMD+"export", args);  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/8a6e703ecf150ccbb38228bc247a4330c977f310/bookmarks.js/clean/browser/components/bookmarks/content/bookmarks.js