I am doing a notification system. When a new post is published, users will be notified immediately by an small notification on the screen.

I am currently using this:

setInterval(function(){
 checkForChanges();
}, 2*1000); 



function checkForChanges(){
    $.post("http://"+ document.domain + "/posts/checkForChanges/",
        function(dat){
           if(dat>0){
              ....
              /*create notification*/
           }

    });
}

And i was wondering if this is the correct way to do it or not. Because, this is calling a PHP function every 2 seconds and making a query to the database. In case there are no new changes, it won't do anything...

Thanks.