repl.ejs("
var f=function() {\n       
var wm = Components.classes[\"@mozilla.org/appshell/window-mediator;1\"]\n.getService(Components.interfaces.nsIWindowMediator);\n
var win = wm.getMostRecentWindow('navigator:browser');\n        
if (! win) {\n// No browser windows are open, so open a new one.\n          
win = window.open('about:blank');\n };\n        
return win.getBrowser()\n    }\n;\n;
f",""
);