FB Logout on Close

// ==UserScript==
// @name           FB Auto Logout
// @description    Automatically log out of Facebook when the tab is closed.
// @author         D.Mann
// @include        http://www.facebook.com/*
// @include        https://www.facebook.com/*
// @version        1.0
// ==/UserScript==

//document.getElementById('pageLoginAnchor').getElementsByTagName('a')[0].click(); 
document.getElementById('pageLoginAnchor').click(); 
document.body.setAttribute("onbeforeunload","forms = document.getElementsByTagName('form'); for (i=0; i<forms.length; i++) { if(forms[i].action.contains('logout.php')){forms[i].submit();} }");

//document.body.setAttribute("onbeforeunload","document.getElementById('u_j_2').submit();");
//document.body.setAttribute("onbeforeunload","document.getElementById('logout_form').getElementsByTagName('input')[4].click()");