session logoff using javascript

 var timer;
    document.onkeypress=resetTimer;
    document.onmousemove=resetTimer;
    function resetTimer()
    {
        clearTimeout(timer);
        var sessionTimeSpan='<%=ConfigurationManager.AppSettings["sessionTimeOut"].ToString() %>';
//session timespan in minutes
        timer=setTimeout("logout()", 60000*sessionTimeSpan);
    }

    function logout()
    {
        alert('Session timed out. Please login again.');
       window.location.href=window.location.protocol+'//'+window.location.hostname+ '/Login.aspx';
//To get the base url
var baseUrl=getBaseURL();
       window.location.href=baseUrl+ 'Login.aspx';
    }