How can session variables be effectively used to store and compare Captcha codes in PHP forms?

When using Captcha codes in PHP forms, session variables can be effectively used to store the generated code and compare it with the user input to validate the form submission. This helps prevent automated bots from submitting the form. By storing the Captcha code in a session variable, you can easily compare it with the user input when the form is submitted. 

// Start the session
session_start();

// Generate a random Captcha code
$captcha_code = substr(md5(rand()), 0, 6);

// Store the Captcha code in a session variable
$_SESSION['captcha_code'] = $captcha_code;

// Display the Captcha image with the generated code

// Validate the user input against the stored Captcha code
if(isset($_POST['captcha_input'])){
    if($_POST['captcha_input'] == $_SESSION['captcha_code']){
        // Captcha code is correct, process the form submission
    } else {
        // Captcha code is incorrect, display an error message
    }
}

Keywords

session variables Captcha codes PHP forms comparison storage

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