Clear form after submit and page refresh - Wordpress - php

Question

I know that the correct way to insert the data is using AJAX, but I don't mind if the page refreshes. Can anybody help me clear the form data after the page refreshes? Everything works fine, the data is being submitted to the table, and the page refreshes. But if I hit the refresh button again, it tells me that the data will be submitted ... and I don't know what to do.
<?php
$current_user = wp_get_current_user();
if ( $current_user->ID == 0 ) {
} else {
if( isset( $_POST['drop_artists'] ) ) {
$answer = $_POST['drop_artists'];
}else{
$answer = $_POST['artist_name'];
}
$date = current_time( 'mysql' );
$table = "t4t5_answers";
$sql = $wpdb->prepare( "INSERT INTO $table (user_id, post_id, info, answer, submission_date ) VALUES ( %d, %d, %s, %s, %d )", $current_user->ID, $post->ID, 'artist', $answer, $date );
$wpdb->query($sql);
header('Location: ' . get_bloginfo('url'));
}//if(isset($_POST['form_sub']))
?>
<form method="post" action="" id="artists-form">
<ul>
<li id="categories">
<?php
$args = array(
'show_option_all' => 'Artists',
'hierarchical' => 1,
'child_of' => 406,
'order_by' => 'name',
'name' => 'answer',
'hide_empty' => 0
);
wp_dropdown_categories($args); ?>
</li>
</ul>
<input type="text" name="artist_name" value="" size="45" id="input-title"/>
<input id="submitButton" class="subput" type="submit" name="submit" value="Add"/>
</form>

Answer 1

After the page is posted, use a redirect to send te user to a success page. This will make the page that was actually posted not appear in their history.
if (!empty($_POST)) {
// do stuff
header("Location: $_SERVER[PHP_SELF]");
}
Note the URL for the redirect should be a full URL, not a relative one. In practice though, I haven't seen any browsers have a problem with the relative URL.

Answer 2

To redirect to your current url immediately, try this one
echo '<META HTTP-EQUIV=Refresh CONTENT="0; URL='.$current_URL.'">'
for more details see http://en.wikipedia.org/wiki/Meta_refresh

Answer 3

Write your php code inside if(isset($_POST['submit']) and add following script below insert statement.
echo " <script type='text/javascript'>
window.location=document.location.href;
</script>";
Your code will look like the following:
global $wpdb,$post;
if(isset($_POST['submit']))
{
$current_user = wp_get_current_user();
if ( $current_user->ID == 0 )
{
}
else
{
if( isset( $_POST['drop_artists'] ) )
{
$answer = $_POST['drop_artists'];
}
else
{
$answer = $_POST['artist_name'];
}
$date = current_time( 'mysql' );
$table = "t4t5_answers";
$sql = $wpdb->prepare( "INSERT INTO $table (user_id, post_id, info, answer, submission_date ) VALUES ( %d, %d, %s, %s, %d )", $current_user->ID, $post->ID, 'artist', $answer, $date );
$wpdb->query($sql);
}
echo "<script type='text/javascript'>
window.location=document.location.href;
</script>";
}
?>
<form method="post" action="" id="artists-form">
<ul>
<li id="categories">
<?php
$args = array(
'show_option_all' => 'Artists',
'hierarchical' => 1,
'child_of' => 406,
'order_by' => 'name',
'name' => 'answer',
'hide_empty' => 0
);
wp_dropdown_categories($args); ?>
</li>
</ul>
<input type="text" name="artist_name" value="" size="45" id="input-title"/>
<input id="submitButton" class="subput" type="submit" name="submit" value="Add"/>
</form>
This will refresh your page after form submit and form values will not be resubmitted.