Refresh random post list on click

in my single.php i have code that will show 6 random post as a ul

How can i add button that will refresh only my wp_query on click?

Here is my code:

<?php $random_post = new WP_query();  ?>
<?php $random_post->query('showposts=6&orderby=rand');  ?>
<?php while ($random_post->have_posts()) : $random_post->the_post();  ?>

<?php
if (has_post_thumbnail()) {
echo '<div class="small-index-thumbnail">';
echo '<li> <a href="' .
get_permalink() . '" title="' . __('Read: ', 'theme-zero') . get_the_title() . '" rel="bookmark">';

echo the_post_thumbnail('index-thumb');

echo get_post_meta($post->ID,'incr_number',true) . '. ';
echo the_title() . '</a></li></div>';

}
?> 



<?php endwhile; ?>
<?php wp_reset_postdata(); ?>