HTML PHP上传不上传文件

Question

使用HTML表单将文件发布到PHP并将该文件上载到指定的文件夹。

PHP正在返回“成功”但该文件尚未上传。该文件夹存在，但没有文件上传。

Q. Why is this file not being successfully uploaded?

错误检查此行时会返回错误

foreach($_FILES['files']['tmp_name'] as $key => $tmp_name ){

错误 注意：未定义的索引：第21行的脚本/ uDoc.php中的文件警告：在第21行的脚本/ uDoc.php中为foreach（）提供的参数无效

HTML

<form id='licenseForm' method='POST' action='scripts/uDoc.php' enctype="multipart/form-data">
        <input type='file' name="files" id='license_upload_btn' />
        <input type='hidden' name='uid' value='{member_id}' />
        <input type='hidden' name='docType' value='license' />
</form>

PHP

$errors= array();

foreach($_FILES['files']['tmp_name'] as $key => $tmp_name ){
    $file_name = $key.$_FILES['files']['name'][$key];
    $file_size =$_FILES['files']['size'][$key];
    $file_tmp =$_FILES['files']['tmp_name'][$key];
    $file_type=$_FILES['files']['type'][$key];   


    $desired_dir="uDocs";

    if(empty($errors)==true){
        if(is_dir($desired_dir)==false){
            mkdir("$desired_dir", 0700);// Create directory if it does not exist
        }
        if(is_dir("$desired_dir/".$file_name)==false){
            move_uploaded_file($file_tmp,"image_uploads/".$file_name);
        }else{                                  //rename the file if another one exist
            $new_dir="image_uploads/".$file_name.time();
            rename($file_tmp,$new_dir) ;               
        }
    }else {
        print_r($errors);
    }
}
if(empty($error)){
    echo "Success";
}