Question

How can I find out what parameters were passed to an (asynchronous) jQuery AJAX request after it is complete?

Basically, I am firing a bunch of AJAX requests with different id passed as a parameter and displaying the results to the user when each of them finishes. Now, if the request is successful, I can pass the id back in the result of the request. But, if the request fails, I don’t know which request failed, i.e. for what id was that request.

Example (javascript/jQuery):

for(var i=0; i < 10; i++ ) {

    $.ajax({
        type: "GET",
        url: "get-results.php", 
        data: { 'id': i },
        success: function(data, textStatus, xmlReq) {

            data = $.parseJSON(data);
            $("#result" + data.id).html(data.result);

        },
        error: function(xmlReq, textStatus, errorThrown) {

            var id= ???;
            $("#result" + id).html('error bla bla');

        }
   });
}

Answer 1

You need to capture the current value of i for the error function. And you capture with a closure. So:

error: function(id) {
    return function(xmlReq, textStatus, errorThrown) {

        $("#result" + id).html('error bla bla');

    };
}(i)

That is error is the result of immediately calling an anonymous function passing in the current value of i.