完成ajax，然后重新开始

I'm working on a php-ajax chat, and I use two main methods: "update" and "send"

Update function (ajax):

$.ajax({
    type: 'POST',
    timeout: 9999999999999999,
    url: 'process.php',
    success: ...
});

Process.php:

function update(){
   if(new messages){
   echo new messages...
   }else{
   sleep(5);update(); again...
   }
}

Send function (ajax):

$.ajax({
type: "POST",
url: "send.php",
success: function(){
update();}
})

I want to stop running "update" request when sending new message and start it again immediently, so sender will instantly see his message. I have tried ajax.abort() but it can still continue to execute the call on server side.

How can I complete the ajax call and make return success, not aborting it?

In your PHP code you could check for connection aborted http://php.net/manual/en/function.connection-aborted.php

But if you realy want to return "success" I would add something to the session in send.php like

$_SESSION['SENDNOW']=true;

and then in the Process.php I would check for

if(new messages || $_SESSION['SENDNOW']==true){
   $_SESSION['SENDNOW']=false;
}

perhaps you should make the timeout 1sec for quicker response times. Or if you do it perfectly you could check quickly (like every 500ms) for $_SESSION['SENDNOW']==true and only every 5seconds for new messages

Please try this:

First document.ready() function declares an Ajax call as variable like below:

var ajaxCall = null;

Put this code in within your AJAX function at top:

//AJAX request aborted
if ( typeof ajaxCall != 'undefined' ) {
     return false;
}

For call to AJAX like this:

ajaxCall = $.ajax({
    type: 'POST',
    timeout: 9999999999999999,
    url: 'process.php',
    success: ...
});

So every time not call to server.