(JQuery) How to call a custom function before following link

You might want to see my answer to a similar question. Basically, an ajax post would be asynchronous by default and may not make it to the server before completing. In order to ensure completion, you can make it synchronous but this will lock up the browser until the request has returned. This can be very problematic if your server is having trouble, it could take a while and the user is waiting to follow the link. Nevertheless, the code is:

$('#hotlink').click( function () { 
    $.ajax({ 
      async: false,
      type: "POST", 
      url: "http://myurl.com/mypage.php", 
      data: "param1=value&param2=value",  // &param3=value... etc. 
    }); 
}); 

Upon completion, the default action of the link will be honoured.

http://stackoverflow.com/questions/2274949/why-cant-i-use-jquery-to-fire-an-ajax-request-from-an-unload-event-handler/2274996#2274996