Upload documents in php

The content of the $ _ FILES array uploaded by php is as follows:

$ _ FILES ['myfile'] ['name'] original name of the client file.
$ _ FILES ['myfile'] ['type'] indicates the MIME type of the file, which must be supported by the browser, for example, "image/gif ".
$ _ FILES ['myfile'] ['size'] size of the uploaded file, in bytes.
$ _ FILES ['myfile'] ['tmp _ name'] temporary file name stored on the server after the file is uploaded, which is generally the default file name. It can be specified in upload_tmp_dir of php. ini, but the putenv () function setting does not work.
$ _ FILES ['myfile'] ['error'] error code related to the file upload. ['Error'] is added in PHP 4.2.0. The following is its description: (they become constants after PHP3.0)
UPLOAD_ERR_ OK
Value: 0. If no error occurs, the file is uploaded successfully.
UPLOAD_ERR_INI_SIZE
Value: 1; the uploaded file exceeds the limit of the upload_max_filesize option in php. ini.
UPLOAD_ERR_FORM_SIZE
Value: 2; the size of the uploaded file exceeds the value specified by the MAX_FILE_SIZE option in the HTML form.
UPLOAD_ERR_PARTIAL
Value: 3; only part of the file is uploaded.
UPLOAD_ERR_NO_FILE
Value: 4; no file is uploaded.
Value: 5; the size of the uploaded file is 0.

The filesize () function returns the size of the specified file.

The is_uploaded_file () function checks whether the specified file is uploaded through http post.