What is the best practice for passing selected values from a dropdown list in PHP forms?

When passing selected values from a dropdown list in PHP forms, it is best practice to use the $_POST superglobal to retrieve the selected value. This ensures that the selected value is securely passed from the form to the server-side script for processing. Additionally, it is important to sanitize and validate the selected value to prevent any potential security vulnerabilities. 

// HTML form with dropdown list
<form method="post" action="process_form.php">
    <select name="dropdown">
        <option value="option1">Option 1</option>
        <option value="option2">Option 2</option>
        <option value="option3">Option 3</option>
    </select>
    <input type="submit" value="Submit">
</form>

// process_form.php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $selectedValue = $_POST['dropdown'];
    
    // Sanitize and validate the selected value
    $selectedValue = filter_var($selectedValue, FILTER_SANITIZE_STRING);
    
    // Use the selected value for further processing
    echo "Selected value: " . $selectedValue;
}

Keywords

PHP form handling dropdown list selected values data submission

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