Blueimp jquery上传获取上传按钮的数据属性

Question

我在页面上使用jquery选项卡，上面有多个上传表单。我正在初始化Fileupload，如下所示：

    $('.fileupload').fileupload({
    url: '<?php echo SITE_URL; ?>/uploads/index.php?property_id=<?php echo $property_id; ?>&category_id='+SubCategoryID,
    });

在我的页面中，我有这样的文件上传表单：

    <form id="files-form-<?php echo $s_value['sub_id']; ?>" class="fileupload" action="#" method="POST" enctype="multipart/form-data">
    // $s_value['sub_id'] is the actual id of category/subcategory and it's pulled out from an array
    ...STANDARD STUFF...
            <div class="fileupload-buttons">
            <span class="fileinput-button">
                <span>Add files...</span>
                <input type="file" name="files[]" multiple>
            </span>
            <button type="submit" class="start" data-subcateogryid="<?php echo $s_value['sub_id']; ?>">Start all uploads</button>
            <span class="fileupload-process"></span>
            ...STANDARD STUFF...
        </div>
     </form>

所以我的问题是：如何将data-subcategoryid作为“GET”变量添加到Fileupload url（在我的JS部分中，它的“SubCategoryID”最后需要用data属性替换）？