How can I abort an AJAX request in ajaxStart or ajaxSend?

Question

My requirement is ,I have written lots of $.post method in my project. I want to check the session in every request and depending upon the session value, I want to handle my page.But I don`t want to modify all methods($.post) for session, So I want to check the session in "ajaxStart or ajaxSend" and depending upon the response I want to abort the main AJAX call.

I have tried with my little knowledge.The below sample code is not working,because $.post is asynchronous.Could any one help me to abort an AJAX Request in ajaxStart or ajaxSend state?

var pp;
link=function(id){
var url="http://localhost/jqueryui/test.php";
    pp=$.post(url,{"id":id},function(data){
        $("#div"+id).html(data);
    });
}
$(function(){
    $("#loading").ajaxStart(function(){
        alert("Hi start");
        $(this).show();
               var url="http://localhost/jqueryui/test.php";
           $.post(url,{"id":99},function(data){//checking the session
            if(data == "close")
            pp.abort();         
            });
    }); 
});

Answer 1

You can abort the request by using the second paramter "jqXHR" in the callback:

$( document ).ajaxSend( function( event, jqXHR, ajaxOptions )
{
    jqXHR.abort(); // aborts the ajax request
} );

Answer 2

See beforeSend(jqXHR, settings) from the jQuery website. I don't know what version of jQuery you were using, but the docs say that you can return false from beforeSend to cancel.