Ajax polling

ajaxpolling.js

if(typeof(Storage) !== "undefined") {

    var d = new Date();
    var n = Math.round(d.getTime() /1000);

    if (sessionStorage.toralarmvisit) {

    } else {
        sessionStorage.toralarmvisit = n;
    }

    $.ajax({
       type: "GET",
       url: urlPrefix + "/wm2014/toralarm",
       datatype: 'json',
       data: {  naked: true, toralarmvisit: sessionStorage.toralarmvisit }
   }).done(function( msg ) {
        msg = JSON.parse(msg);
        if(msg.status){
            $('#toralarminfo').html(msg.data);
            $('#toralarm').fadeIn();
            sessionStorage.toralarmvisit = msg.tmstamp;
        }
   });
}