问上传大图片时，在网络连接中止后恢复还是重新启动ajax请求？

EN

var run = function(){        
         Offline.check();
    }

    setInterval(run, 3000);

Offline.on('up', function(){
if(ajax_response === null || ajax_response == 'error')
{
    rename_file (oldname,newname)
}
});         

    var ajax_response = null;
window.rename_file = function(oldname,newname)
    {
        var resp =null;

        $.ajax({            
            url:'ajaxcall.php',
            data:{action:'rename_file',new_name:newname,old_name:oldname},  
            async:false,            
            success:function(data,status)
            {
                resp = 'success';
            },
            error: function(jqXHR, textStatus, errorThrown) {               
                resp = 'error';                 
            }
        });

        ajax_response.= resp;
        return resp;
    }