Share URL strings from variables

shareurls.php

<?php
$tweet_url = 'http://twitter.com/intent/tweet'
       . '?text=' . urlencode($PAGE_TITLE)
       . '&url=' . urlencode($PAGE_URL)
       . '&via=' . $TWITTER_UN;
       
$facebook_url = 'https://www.facebook.com/dialog/feed'
          . '?app_id=' . urlencode(FACEBOOK_APP_ID)
          . '&link=' . urlencode($PAGE_URL)
          . '&name=' . urlencode($PAGE_TITLE)
          . '&description=' . urlencode($SHARE_DESCRIPTION)
          . '&redirect_uri=' . urlencode($PAGE_URL);