Mac Safari 11.10下Ajax文件上传遇408请求超时问题求助

我在 Mac 的 Safari 11.10 浏览器里使用 Ajax 上传文件时，遇到了请求超时的问题，错误信息如下：

Failed to load resource: the server responded with a status of 408 (Request Timeout)

我的前端代码如下：

var formData = new FormData($("#designer_product_updateform")[0]); 
var prodesc = CKEDITOR.instances['product_edesc'].getData(); 
formData.append("product_edesc",prodesc); 
formData.append('action', "updateDesignerProduct"); 
$("#addproducttabajaxloader").css("display","block"); 
$.ajax({ 
    type:"POST", 
    url:"includes/ajax_product.php", 
    data:formData, 
    cache:false, 
    contentType:false, 
    processData:false, 
    success:function(response){ 
        $("#addproducttabajaxloader").css("display","none"); 
        var parseval = jQuery.parseJSON(response); 
        var code = parseval.code; 
        var message = parseval.message; 
        if(code == "201") { 
            var message_html = '<div class="alert alert-success alert-dismissable" id="attdone"><button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>'+ message +'</div>'; 
            jQuery("#yajaxmessage").html(""); 
            jQuery("#yajaxmessage").html(message_html); 
            setTimeout(function(){ 
                window.location.href = "myaccount.php?t=pl"; 
            }, 1000); 
        } else if(code == "200") { 
            var message_html = '<div class="alert alert-danger alert-dismissable" id="attdone"><button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>'+ message +'</div>'; 
            jQuery("#yajaxmessage").html(""); 
            jQuery("#yajaxmessage").html(message_html); 
        } 
    } 
}) 
return false; 
} 
}); 

我已经试了好几种解决方案，但都没能解决这个问题，恳请各位帮忙排查一下，提前致谢！

内容的提问来源于stack exchange，提问作者Rahul