How does PHP handle requests and responses when submitting a form multiple times?

When submitting a form multiple times, PHP can handle the requests and responses by using session variables to prevent duplicate form submissions. By setting a flag in the session when the form is submitted, we can check if the form has already been processed before processing it again. 

session_start();

if(isset($_POST['submit'])) {
    if(!isset($_SESSION['form_submitted'])) {
        // Process the form data
        $_SESSION['form_submitted'] = true;
    } else {
        // Form has already been submitted
        echo "Form has already been submitted.";
    }
}

Keywords

PHP form submission request handling response handling form resubmission

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