用这种方式访问
$_FILES['userfile']['name']
The original name of the file on the client machine. $_FILES['userfile']['type']
The mime type of the file, if the browser provided this information. An example would be "image/gif". $_FILES['userfile']['size']
The size, in bytes, of the uploaded file. $_FILES['userfile']['tmp_name']
The temporary filename of the file in which the uploaded file was stored on the server. $_FILES['userfile']['error']
The error code associated with this file upload. ['error'] was added in PHP 4.2.0
$_FILES['userfile']['name']
The original name of the file on the client machine. $_FILES['userfile']['type']
The mime type of the file, if the browser provided this information. An example would be "image/gif". $_FILES['userfile']['size']
The size, in bytes, of the uploaded file. $_FILES['userfile']['tmp_name']
The temporary filename of the file in which the uploaded file was stored on the server. $_FILES['userfile']['error']
The error code associated with this file upload. ['error'] was added in PHP 4.2.0
是我的电脑问题，也不知道出了什么问题！放到服务器上就没有问题了。