PHP Form Handling:

Reading Data from Web Form Controls and File Uploads

Reading Data from Text Boxes, Radio Buttons, Lists, etc.

PHP allows reading data from web form controls using superglobal arrays like $_GET and $_POST. These controls include:

• Text boxes

• Radio buttons

• Checkboxes

• Select lists (dropdowns)

• Text areas

When a user submits a form, the data is sent to the server for processing. This is done using either the GET or POST method.

Example: HTML Form Using POST

<form action="welcome.php" method="post">
Name: <input type="text" name="name"><br>
E-mail: <input type="text" name="email"><br>
<input type="submit">
</form>

Example: PHP Script (welcome.php)

Welcome <?php echo $_POST["name"]; ?><br>
Your email address is: <?php echo $_POST["email"]; ?>

If the method is set to GET, use $_GET["name"] and $_GET["email"] instead.

GET vs POST

GET:

• Appends data in the URL

• Data is visible

• Limited to ~2000 characters

• Can be bookmarked

• Not secure for sensitive information

POST:

• Sends data in HTTP body

• Not visible in URL

• No data limit

• Suitable for sensitive and large data

• Required for file uploads

Accessing Form Data in PHP

Example: Reading Form Values

if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $name = $_POST['name'];
  $gender = $_POST['gender'];
  $hobbies = $_POST['hobbies'];
  $country = $_POST['country'];
}

Validating and Sanitizing Form Inputs

To protect from security issues like SQL injection or XSS, always validate user input.

Example: Basic Validation

$name = trim($_POST['name']);
if (!empty($name)) {
  $name = htmlspecialchars($name);
} else {
  echo "Name is required.";
}

Handling File Uploads in PHP

PHP supports file uploads using the $_FILES superglobal. You must set the form’s enctype to multipart/form-data.

Example: HTML Form for File Upload

<form action="upload.php" method="post" enctype="multipart/form-data">
Select file: <input type="file" name="myFile"><br>
<input type="submit" value="Upload">
</form>

Example: PHP Script (upload.php)

if ($_FILES["myFile"]["error"] == 0) {
  move_uploaded_file($_FILES["myFile"]["tmp_name"], "uploads/" . $_FILES["myFile"]["name"]);
  echo "File uploaded successfully.";
} else {
  echo "File upload error.";
}

Key Points for File Uploads:

• Always check for upload errors.

• Validate file type and size.

• Use move_uploaded_file() to store the file safely.

• Set proper file permissions on the server.

Conclusion

Reading data from form controls and handling file uploads are essential in PHP web applications. Use POST for secure data handling and always validate user input. With careful processing, you can create powerful, user-friendly, and secure web forms.