<script type="text/javascript">
         // transfers sessionStorage from one tab to another
         console.log("1");
         var sessionStorage_transfer = function (event) {
             console.log("2");
             if (!event) { event = window.event; } // ie suq
             console.log("3; " + window.veent);
             alert('Estimado usuario, este sitio se encuentra activo en otra pestaña del navegador.');
             //location.href = "../../../FinSesion.aspx";
             if (!event.newValue) return;          // do nothing if no value to work with
             console.log("4");
             if (event.key == 'getSessionStorage') {
                 console.log("5");
                 // another tab asked for the sessionStorage -> send it
                 localStorage.setItem('sessionStorage', JSON.stringify(sessionStorage));
                 console.log("6; " + sessionStorage);
                 // the other tab should now have it, so we're done with it.
                 localStorage.removeItem('sessionStorage'); // <- could do short timeout as well.
                 console.log("7");
             } else if (event.key == 'sessionStorage' && !sessionStorage.length) {
                 console.log("8; " + sessionStorage.length);
                 // another tab sent data <- get it
                 var data = JSON.parse(event.newValue);
                 console.log("9");
                 for (var key in data) {
                     console.log("10; " + data[key]);
                     sessionStorage.setItem(key, data[key]);
                 }
                 console.log("11");
             }
             console.log("12");
         };
         // listen for changes to localStorage
         if (window.addEventListener) {
             console.log("13");
             window.addEventListener("storage", sessionStorage_transfer, false);
             console.log("14; " + sessionStorage_transfer.length);
         } else {
             console.log("15");
             window.attachEvent("onstorage", sessionStorage_transfer);
             console.log("16");
         };

         console.log("17");
         // Ask other tabs for session storage (this is ONLY to trigger event)
         if (!sessionStorage.length) {
             console.log("18; " + sessionStorage.length);
             localStorage.setItem('getSessionStorage', 'foobar');
             console.log("19");
             localStorage.removeItem('getSessionStorage', 'foobar');
             console.log("20");
         };
         console.log("21");
    </script>