PHP form handling involves collecting, validating, and processing data submitted through HTML forms. PHP uses the $_GET and $_POST superglobals to retrieve form data based on the HTTP request method.

Collecting Data: Retrieves submitted values from form fields.
Validating Data: Checks whether inputs meet expected requirements.
Processing Data: Uses the submitted data for tasks such as saving records or sending emails.
Displaying Responses: Shows confirmation messages or redirects users after submission.

Form Attributes to Submit Data

HTML form attributes control where and how form data is submitted.

Attribute	Description
action	Specifies the URL or PHP script that processes the form.
method	Specifies the HTTP method, usually `GET` or `POST`.
name	Identifies a form field so its submitted value can be accessed in PHP.
target	Specifies where to display the response, such as the current tab or a new tab.
enctype	Specifies how form data is encoded. Use multipart/form-data for file uploads.

Example:

PHP

<form method="post" action="process_form.php">
    <input type="text" name="username" required>
    <input type="submit" value="Submit">
</form>

Here, the form sends the username to process_form.php using the POST method. PHP can access the submitted value using $_POST['username'].

Different Input Elements to Collect Data

HTML provides several form elements for collecting different types of user input.

Element	Purpose	Example
Text field	Collects single-line text.	<input type="text" name="fullname">
Password field	Hides entered characters visually.	<input type="password" name="password">
Checkbox	Allows users to select one or more options.	<input type="checkbox" name="subscribe" value="yes">
Radio button	Allows users to select one option from a group.	<input type="radio" name="gender" value="female">
Email field	Collects an email address and provides browser-level format checking.	<input type="email" name="email">
Textarea	Collects multiline text.	<textarea name="message"></textarea>
Submit button	Submits the form.	<input type="submit" value="Submit">

Creates and Processes an HTML Form

The following example creates a form and processes its submitted data on the same page.

Example:

PHP

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>PHP Form Handling</title>
</head>
<body>

<form method="post" action="">
    <label>
        Full Name:
        <input type="text" name="fullname" required>
    </label>
    <br><br>

    <label>
        Email:
        <input type="email" name="user_email" required>
    </label>
    <br><br>

    <label>
        Age:
        <input type="number" name="user_age" min="1" required>
    </label>
    <br><br>

    <label>
        Feedback:
        <textarea name="user_feedback" rows="4" required></textarea>
    </label>
    <br><br>

    Gender:
    <label>
        <input type="radio" name="user_gender" value="female" required>
        Female
    </label>

    <label>
        <input type="radio" name="user_gender" value="male">
        Male
    </label>
    <br><br>

    <input type="submit" value="Submit">
</form>

<?php
if (($_SERVER["REQUEST_METHOD"] ?? "") === "POST") {
    $fullname = trim($_POST['fullname'] ?? '');
    $email = trim($_POST['user_email'] ?? '');
    $age = $_POST['user_age'] ?? '';
    $feedback = trim($_POST['user_feedback'] ?? '');
    $gender = $_POST['user_gender'] ?? '';

    if (
        $fullname !== '' &&
        filter_var($email, FILTER_VALIDATE_EMAIL) &&
        filter_var($age, FILTER_VALIDATE_INT, [
            'options' => ['min_range' => 1]
        ]) !== false &&
        $feedback !== '' &&
        in_array($gender, ['female', 'male'], true)
    ) {
        echo "<h2>Details Submitted</h2>";
        echo "Full Name: " . htmlspecialchars($fullname, ENT_QUOTES, 'UTF-8') . "<br>";
        echo "Email: " . htmlspecialchars($email, ENT_QUOTES, 'UTF-8') . "<br>";
        echo "Age: " . htmlspecialchars((string) $age, ENT_QUOTES, 'UTF-8') . "<br>";
        echo "Feedback: " . htmlspecialchars($feedback, ENT_QUOTES, 'UTF-8') . "<br>";
        echo "Gender: " . htmlspecialchars($gender, ENT_QUOTES, 'UTF-8');
    } else {
        echo "Please provide valid form data.";
    }
}
?>

</body>
</html>

Form Submission: The HTML form sends user data to the same page using the POST method.
Request Checking: $_SERVER['REQUEST_METHOD'] checks whether the current request uses the POST method.
Data Retrieval: $_POST retrieves the submitted form values, while the null coalescing operator (??) provides default values if keys are missing.
Validation: filter_var() validates the email address and age, while additional checks ensure that the required fields are not empty and the gender value is valid.
Output Escaping: htmlspecialchars() escapes user-provided values before displaying them in HTML, helping prevent cross-site scripting (XSS).

Output:

Before submission, the page displays fields for the user's name, email, age, feedback, and gender.

After submitting valid data, PHP displays the submitted details.

Note: htmlspecialchars() helps prevent cross-site scripting (XSS) when displaying data in HTML, but it does not validate input. For applications that store submitted data in a database, use prepared statements to help prevent SQL injection.

PHP Form Handling

Form Attributes to Submit Data

Different Input Elements to Collect Data

Creates and Processes an HTML Form

Explore