Question

I have been trying to create a timer that will log my clients out when they have been idol for over 10 minutes. I have created the code below which works fine as long as the user does not open a second tab. I have many clients that open a second window or tab and while the second tab is open the counter speeds up. I am looking for a way to improve the following code so that the tabs/windows can be in better sync.

var cookies='off'; // var to check if cookies are turned off
var alertTimes=0; // alturnative to cookies
$(function(){
    resetCookies();
    var loginTime=getCookie("loginTime");
    if (loginTime!=null && loginTime!=""){ cookies='on'; }
    checkAlerts();
});

function resetCookies(){
    setCookie("loginTime",'10',1);
    alertTimes=0;
}
function checkTime() {
    if(cookies=='on'){
        var loginTime=getCookie("loginTime");
        if (loginTime!=null && loginTime!=""){ 
            var newTime=loginTime-1;
            if(newTime==0){ autoLogout(); return false;}
            setCookie("loginTime",newTime,1);
        }else{ autoLogout(); return false;}
    }else{
        alertTimes++;
        if(alertTimes>=10){ autoLogout(); return false;}
    }
    setTimeout(checkTime, 600000);
}
function setCookie(c_name,value,exdays){
    var exdate=new Date();
    exdate.setDate(exdate.getDate() + exdays);
    var c_value=escape(value) + ((exdays==null) ? "" : "; expires="+exdate.toUTCString());
    document.cookie=c_name + "=" + c_value;
}
function getCookie(c_name){
  var i,x,y,ARRcookies=document.cookie.split(";");
  for (i=0;i<ARRcookies.length;i++){
    x=ARRcookies[i].substr(0,ARRcookies[i].indexOf("="));
    y=ARRcookies[i].substr(ARRcookies[i].indexOf("=")+1);
    x=x.replace(/^\s+|\s+$/g,"");
    if (x==c_name){ return unescape(y); }
  }
}
function autoLogout(){
    window.location.href=("logout.php");
}

Answer 1

Maybe this example will satisfy your needs?

( function ( $ ) {
  $.loginTimeout = function ( options ) {

    var opts = $.extend( {}, $.loginTimeout.defaults, options ),
    callback = function() {
      $.getJSON( opts.url, function ( data ) {
        if(data.status === "signed_out")
        document.location = opts.redirectTo;
      });
    };
    setInterval( callback, opts.timeout * 1000 );
  };

  $.loginTimeout.defaults = {
    timeout: 60,
    redirectTo: "/login",
    url: "/check_login"
  };
} ( jQuery ) );
// ...
$.loginTimeout({
  redirectTo: "/users/sign_in",
  url: "/users/check_status"
});

also keep in mind that in this example server application is deciding if user session has expired