jQuery Ajax加载顺序

I have a jQuery Ajax function that requests data from the server.

The code finds all spans, gets their IDs and sends it to the json.php for a result. Each id returns a different value and their load times are different. Say one loads instantly and the other loads in 10 seconds.

Whats wrong: Ok, once the page loads, all requests are sent to json.php, but if the third span is going to return a result instantly, it WAITS for the first two to load first!!

Scenario: I have 3 spans, the first one must be returned in 9 seconds, the seconds one must be returned in 4 seconds, and the third one must load in 5 seconds. Here is what happens: The first span appears after 9 seconds, the seconds span appears after 9+4 seconds and the last one loads in 9+4+3 seconds.

Here is the code:

<script>
function getData(d){
    var r=Math.floor(Math.random()*500)
    $('#'+d).addClass('load');
    var handler = '';
    $.get('json.php?request='+d+'&r='+r, function(data) {
                var obj = jQuery.parseJSON(data);
                for (var i = 0; i < obj.length; i++) {
                    var object = obj[i];
                    for (property in object) {
                            handler = object[property];
                                $('#'+d).removeClass('load');
                                $('#'+d).html(handler);
                    }
                }
    });
    return true;
}

$(document).ready(function() {
    $("span").each(function() {               
         getData($(this).attr('id'));
     });
});
</script>

            <span id="first_data"></span>
            <span id="second_data"></span>
            <span id="third_data"></span>

Anything wrong here??