php - Displaying Message After Redirecting -

what best way display success message after submitting form , redirecting.

i'm developing script smarty template engine , don't want use javascript want easy possible user design or own template , have tried using sessions display message seems unset after redirecting example

the form

<form action="" id="comment_form" method="post">     <input type="hidden" name="movie_id" id="page_id" value="{$mov.mid}" />     <input type="hidden" name="user_id" id="user_id" value="{$logged_id}" />     <input class="span2" name="comment" type="text" />     <button class="btn" name="add_comment" type="submit">add comment</button> </form> 

php

if (isset($_post['add_comment'])) {     if (!empty($_post['comment'])) {         $user_id = $logged_id;         $post_comment = mysqli_real_escape_string($con, $_post['comment']);         $movie->addmoviecomments($con, $movie_id,  $user_id, $post_comment);         $_session['insert'] = 'success';         header ('location: '.$_server['request_uri']);     } else {         $_session['insert'] = 'empty';     } } 

now trying display success in tpl

{if isset($smarty.session.insert)}     <div class="alert alert-success">         <button type="button" class="close" data-dismiss="alert">&times;</button>         <h4>success</h4>         comment added     </div> {/if} {php}unset($_session['insert']);{/php} 

so can me out , tell me best way or tell me why unset before displayed.

try

if( isset($_session['insert']) && $_session['insert'] == 'success') { //your alert unset($_session['insert']); }