保持Ajax连接15分钟

Question

我希望保持从Ajax到PHP Script的连接打开，以便我的CSV成功加载到数据库中。目前它在30秒时切断。以下是JavaScript。

我无法使用php来设置超时，因为RackSpace Load Balancer会切断30秒无效的脚本。

(function() {

    var bar = $('.bar');
    var percent = $('.percent');
    var status = $('#status');

    $('form#bulk-upload').ajaxForm({
            beforeSend: function() {
                    status.empty();
                    var percentVal = '0%';
                    bar.width(percentVal)
                    percent.html(percentVal);
            },
            uploadProgress: function(event, position, total, percentComplete) {
                    var percentVal = percentComplete + '%';
                    bar.width(percentVal)
                    percent.html(percentVal);
            //console.log(percentVal, position, total);
            },
            success: function() {
                    var percentVal = '100%';
                    bar.width(percentVal)
                    percent.html(percentVal);
            },
        complete: function(xhr) {
            data = xhr.responseText;
            var data = data.split("|");
            var code = $.trim(data[0]);
            var msg = $.trim(data[1]);
            if( code == 1 ){
                $("#ajax-msg").addClass("alert alert-success").html(msg);
            } else {
                $("#ajax-msg").addClass("alert alert-danger").html(msg);
            }
            return true; 
        }
    });
    })();