Ajax实时更新标题

Question

Need to change the html title dynamically if new Posts or any update happens.

$(document).ready(function(){ 


function load_unseen_notification() 
{ 
 $.ajax({ 

  url:"notify.php", 
  method:"POST", 
  data:{user:<?php echo $usr_id;?>}, 
  dataType:"json", 
  success:function(data) 

  { 


   if(data.unseen_notification > 0) 
   { 
    $("title").text(data.unseen_notification);
   } 

  } 

 }); 

} 

load_unseen_notification(); 
setInterval(function(){ 
 load_unseen_notification();; 
}, 5000); 

});

the php file Posts {"notification":"test","unseen_notification":1}

if u open it using notify.php?user=1

i tried many options but nothing worked fine.