array_push not adding 2nd item after page refresh - php

Question

I understand that array_push is not adding a 2nd item because when the page refreshes after adding another item the original one goes away and get's replaced by the most recent entry from the text box.
I am trying to achieve this tactic of trying to either...
a. Have a session remember the next item being added EVEN through a page refresh.
or
b. Just not refresh the page at all.
See demo here: http://query.notesquare.me/home.html/
CODE
<form method="post">
<input type="text" id="input-create-playlist" placeholder="Playlist Name" name="create_playlist" />
<input type="submit" id="button-create-playlist" value="Create Playlist" />
</form>
<?php
session_start();
$create_playlist = $_POST['create_playlist'];
$playlists = array("One", "Two", "Three");
$_SESSION['main'] = $playlists;
array_push($playlists, $create_playlist);
for ($i = 0; $i < count($playlists); $i++) {
echo $playlists[$i] . "<br />";
}
?>

Answer 1

Try
<form method="post">
<input type="text" id="input-create-playlist" placeholder="Playlist Name" name="create_playlist" />
<input type="submit" id="button-create-playlist" value="Create Playlist" />
</form>
<?php
session_start();
$create_playlist = $_POST['create_playlist'];
$_SESSION['user_playlists'][] = $create_playlist;
$playlists = array("One", "Two", "Three");
for ($i = 0; $i < count($_SESSION['user_playlists']); $i++) {
array_push($playlists, $_SESSION['user_playlists'][$i]);
}
$_SESSION['main'] = $playlists;
for ($i = 0; $i < count($playlists); $i++) {
echo $playlists[$i] . "<br />";
}
?>
Your approach was setting the $_SESSION['main'] = $_POST['create_playlist'] before the desired effects of array_push.