How to detect if request is AJAX from JS

Question

I have a messaging system for which I do infinite scroll using jQuery.load. The problem is that the way I set it up, when the response of jQuery.load returns, all JS from the page is ran once again. This is fine, but I want to disable a particular JS block only if the request is an AJAX (jQuery.load).

Is it possible to do something like this?

if(!request_is_ajax){
    run_some_code();
}
else{
    // do nothing
}

Basically the code should run on the main pageload, but not on subsequent calls. I can detect this server-side, but that would be the last resort for me.

maybe you can set a global js variable to false once you loaded the code you want, and then check if it's true when the code executes again. — Bobby5193
– Bobby5193, Commented Apr 30, 2014 at 11:14
@Bobby5193 if you would kindly post the comment as an answer, I'd be glad to accept it. Worked great. No idea why I didn't think of that. — Eduard Luca
– Eduard Luca, Commented Apr 30, 2014 at 11:18

Bobby5193 · Accepted Answer · 2014-04-30 11:22:32Z

1

You can set a global js variable to false once you loaded the code you want, and then check if it's true when the code executes again. I don't think a code snippet is really necessary here.

answered Apr 30, 2014 at 11:22

Bobby5193

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Anup_Tripathi · Accepted Answer · 2014-04-30 11:17:25Z

1

For the subsequent call (ie ajax call after page load) append something like ?ajax or &ajax and check the same on server side to know whether the request is an Ajax request or not.

// a server side php code sample
   $request_is_ajax= @$_GET['ajax']?true:false;
   if(!$request_is_ajax){
        run_some_code();
    }
    else{
        // do nothing
    }

answered Apr 30, 2014 at 11:17

Anup_Tripathi

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Bud Damyanov · Accepted Answer · 2014-04-30 11:18:24Z

0

If you use jQuery, you can check $_SERVER['HTTP_X_REQUESTED_WITH'], which will be set to XMLHttpRequest. This is the most reliable method when using jQuery because the XMLHttpRequest is JavaScript object that makes the request. It's poorly named now, though, because you can have it send whatever you want.

Example code:

/* decide what the content should be up here .... */
$content = get_content(); //generic function;

/* AJAX check  */
if(!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
    /* special ajax here */
    die($content);
}

/* not ajax, do more.... */

answered Apr 30, 2014 at 11:18

Bud Damyanov

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Community · Accepted Answer · 2017-05-23 10:26:06Z

0

You can check in the Responseheader, because $.ajax will send an jqXHR(jQueryXMLHttpRequest).

The statement would be something like this:

    if( jqXHR.getResponseHeader('content-type').indexOf('text/html') >= 0 ) {
    ...
    }

For further information you can look up this stackoverflow answer

edited May 23, 2017 at 10:26

CommunityBot

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answered Apr 30, 2014 at 11:18

KhorneHoly

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