jquery $.ajax request remains pending

Question

I have made a simple chat application which uses long-polling approach using jquery,

function sendchat(){ 
// this code sends the message
$.ajax({
  url: "send.php",
  async: true,
  data: { /* send inputbox1.value */ },
  success: function(data) { }
    });
}

function listen_for_message(){ 
// this code listens for message
$.ajax({
  url: "listen.php",
  async: true,
  timeout:5000,
  success: function(data) { // the message recievend so display that message and make new request for listening new messages 
            $('#display').html(data);
            listen_for_message();
             }
    });
}

THIS SHOULD HAPPEN : after page loaded the infinite request for listen.php occurs and when user sends message, the code sends message to database via send.php.

PROBLEM is, using firebug i've found that send.php request which is performed after listen.php request, is remains pending. means the request for send message is remains pending.

Answer 1

The issue was because of session locking;

both send.php and listen.php files use session variables, so session is locked in listen.php file and the other file (here send.php file) can't be served after the session frees from serving another file ( here listen.php).