Uploading file via html form. In PHP, $_FILES is empty

问题

So I have this code:

<form name="form" action="./" method="post">
<input type="file" name="newfile" id="newfile" />
</form>

When I run this php script on the action page, nothing happens

echo "$_FILES['newfile']['name'];
print_r($_FILES);

It is like the $_FILES variable is empty. Is there any way to fix this?

回答1:

You need to set the enctype="multipart/form-data" attribute on your form.

Example 1 from php.net:

<!-- The data encoding type, enctype, MUST be specified as below -->
<form enctype="multipart/form-data" action="__URL__" method="POST">
    <!-- MAX_FILE_SIZE must precede the file input field -->
    <input type="hidden" name="MAX_FILE_SIZE" value="30000" />
    <!-- Name of input element determines name in $_FILES array -->
    Send this file: <input name="userfile" type="file" />
    <input type="submit" value="Send File" />
</form>

回答2:

If you don't specify <form … enctype="multipart/form-data"> then the data will be encoded in a way that doesn't support files.

Add the attribute with that value.

From the HTML specification:

enctype = content-type [CI]

This attribute specifies the content type used to submit the form to the server (when the value of method is "post"). The default value for this attribute is "application/x-www-form-urlencoded". The value "multipart/form-data" should be used in combination with the INPUT element, type="file".

From the PHP manual:

<!-- The data encoding type, enctype, MUST be specified as below -->
<form enctype="multipart/form-data" action="__URL__" method="POST">

回答3:

echo "$_FILES['newfile']['name'];

That's a syntax error. Should be

echo $_FILES['newfile']['name'];

echo "{$_FILES['newfile']['name']}";

来源：https://stackoverflow.com/questions/8055429/uploading-file-via-html-form-in-php-files-is-empty

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