What should I do if php cannot receive formdata?

PHP is a widely used scripting language often used for server-side programming. Processing of form data submitted by users can be easily implemented using PHP. However, sometimes we encounter such a problem: the data submitted in the form using the FormData format cannot be received in the PHP code. So, how to solve this problem?

First of all, we need to understand the form submission method in FormData format. FormData is a new API for building form data, which can handle forms containing complex data types such as text, files, binary data, etc. When using FormData to submit form data, you must use the POST method.

For example, we can use the following code to create a FormData object containing text and files:

var formData = new FormData();
formData.append('name', 'Bob');
formData.append('file', fileInput.files[0]);

Where, 'name' is the name of the form item, and 'Bob' is its value; 'file' is the name of the file upload control, and fileInput.files[0] is the data of the file. You can use the XMLHttpRequest object to send a FormData object to the server before the form is submitted.

In PHP, there is usually no problem using the $_POST array to receive data submitted by a form. However, if the form uses the FormData format to submit data, you need to use the $_FILES array to receive the data. The $_FILES array contains information about uploaded files.

For example, we can use the following code to receive the data submitted by FormData in PHP:

$name = $_POST['name'];
$file = $_FILES['file'];

Among them, $name is the value of the form item 'name'; $file is the information of the uploaded file.

If there is a problem of not receiving FormData, you can try the following solutions:

1. Check the request header: Use tools such as Fiddler or Chrome Devtools to check the request header submitted by the form to ensure Content-Type is set to 'multipart/form-data'.
2. PHP configuration: Check the PHP configuration file to ensure that configuration items such as file_uploads and post_max_size are set correctly.
3. Upload file size limit: Check whether the upload file size exceeds the limit size set in the PHP configuration file.
4. File upload path: Check whether the saving path of the uploaded file is set correctly.

Summary:

To receive data submitted by FormData in PHP, you need to use the $_FILES array instead of the $_POST array. If there is a problem of not receiving FormData, you need to check the form request header, PHP configuration, upload file size limit, file upload path and other settings.

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