<?php 
$tags = get_tags(array(


  'hide_empty' => false,
  'orderby'       => 'rand', 
  
 
));
$html = '<div class="post_tags">';
foreach ( $tags as $tag ) {
    $tag_link = get_tag_link( $tag->term_id );

    $html .= " <a href='{$tag_link}' title='{$tag->name}' class='{$tag->slug}'>";
    $html .= "{$tag->name}</a>";
}
$html .= '</div>';
echo $html;
?>