每次刷新页面时如何解决发送邮件的问题[重复]

Question

This question already has an answer here:

• Understanding the “post/redirect/get” pattern 3 answers

These form work after submission .but after refreshing the page the mail send again and again.

<?php
$to = "abc.com";
$subject = "This is subject";
$message = "<b>This is HTML message.</b>";
$message .= "<h1>This is headline.</h1>";
$header = "From:[e-mail] 
";
$header .= "MIME-Version: 1.0
";
$header .= "Content-type: text/html
";
$retval = mail ($to,$subject,$message,$header);
if( $retval == true ) {
    echo "Message sent successfully...";
}else {
    echo "Message could not be sent...";
}
?>

</div>

Answer 1

There are multiple ways to handle it.

1) Please write below code after mail sent successfully.

if(!$retval->Send()) {
    header("Location: http://www.example.com");
    exit;
}

2) If that does not work for you, use a meta refresh method:

if(!$retval->Send()) {
    $to = "http://www.example.com";
    $url = $to;
    print "<meta HTTP-EQUIV=Refresh CONTENT=\"5; URL=$url\">";
    print "Thank you for your message.";
    exit;
}

3) You can use a cookie also. To use cookie,you have to create one token which have value of current timestamp and whenever you create cookie with also current timestamp and then compare both variable when page refresh. but cookies has previous timestamp and and token has current timestamp then it will not match.

$token = time();
setcookie('formToken', $token, time() + 3600);

if(isset($_POST['submit'])){

    if($_POST['token'] != $_COOKIE['formToken']){
        // die("Sorry");

        $error_list .= '<li>You can not submit this form twice.</li>';

        echo $error_list;
        echo 'Thank you, your message has been sent. You do not need resubmit it again.';
        exit;

    }

Source