How to prevent form resubmission when page is refreshed (F5 / CTRL+R)

Question

I have a simple form that submits text to my SQL table. The problem is that after the user submits the text, they can refresh the page and the data gets submitted again with

Answer 1

A pretty surefire way is to implement a unique ID into the post and cache it in the

Then in your code do this:

if( ($_SESSION['post_id'] != $_POST['post_id']) )
{
    $_SESSION['post_id'] = $_POST['post_id'];
    //do post stuff
} else {
    //normal display
}

function createPassword($length)
{
    $chars = "abcdefghijkmnopqrstuvwxyz023456789";
    srand((double)microtime()*1000000);
    $i = 0;
    $pass = '' ;

    while ($i <= ($length - 1)) {
        $num = rand() % 33;
        $tmp = substr($chars, $num, 1);
        $pass = $pass . $tmp;
        $i++;
    }
    return $pass;
}