iPhone/iTouch not firing (new Image) request onunload

Hey guys, hope someone can help me out.

I'm making a small application to record clicks, which is going great, until I hit the iPhone/iTouch. I'd like to point out, that I've been testing with an iTouch, and I am just presuming the same thing will happen on a iPhone.

What I have at the moment is something similar to this,

    <script>
    function save(){
        // Capture link, with var mycoords containing string
        var a = 'http://mydomain.com/capture.php?co='+mycoords;
        var img = new Image(1,1);

        // Loads link with params, PHP uses $_GET
        img.src = a;
        alert('f'); // For testing
     }

    // alerts 'f', does not send data on device
    window.onunload = save;

    // alerts 'f', does not send data on device
    window.onunload = (function(){
       save();
    });

    // Alerts 'f', does not send data on device
    window.addEventListener("unload",save,false);
    </script>

This code works on all my desktop browsers, including Safari, but on the iTouch/iPhone, no. If I execute the save() function outside any onunload practice, the data sends just fine. I know the onunload works, due to the alerts. But I am absolutely baffled by image object not working in this instance, yet working everywhere else. I have had a good look about on the net, and have found no solution.

Perhaps someone here can maybe give me a solution or an explanation to why 开发者_如何学JAVAthis is happening? I would be very grateful. Thank you for your time.

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Basically there is no way to detect onunload reliably, as is answered here: javascript unload event in safari mobile?

If you're trying to track clicks, I would suggest adding a click event handler to the link which would first call your save() function and then it could return true or update the document.location.href to take the user to the final link.