<form action="upload_file.php" method="post" enctype="multipart/form-data">
  <label for="file">文件名：</label>
  <input type="file" name="file" id="file"><br>
  <input type="submit" name="submit" value="提交">
</form>

<"gif", "jpeg", "jpg", "png");
$temp = explode(".", $_FILES["file"]["name"]);
echo $_FILES["file"]["size"];
$extension = end($temp);   // 获取文件后缀名
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/jpg")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/x-png")
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 204800)  // 小于 200 kb
&& in_array($extension, $allowedExts))
{
  if ($_FILES["file"]["error"] > 0)
  {
    echo "err";
  }
  else
  {
    echo "上传文件名: " . $_FILES["file"]["name"] . "<br>";
    echo "文件类型: " . $_FILES["file"]["type"] . "<br>";
    echo "文件大小: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
    echo "文件临时存储的位置: " . $_FILES["file"]["tmp_name"] . "<br>";
    
    // 判断当期目录下的 upload 目录是否存在该文件
    // 如果没有 upload 目录，你需要创建它，upload 目录权限为 777
    if (file_exists("../../../Content/UploadFiles/00/00/00/" . $_FILES["file"]["name"]))
    {
      echo "err";
    }
    else
    {
      // 如果 upload 目录不存在该文件则将文件上传到 upload 目录下
      move_uploaded_file($_FILES["file"]["tmp_name"], "../../../Content/UploadFiles/00/00/00/" . $_FILES["file"]["name"]);
    }
  }
}
else
{
  echo "err";
}
?>