Facebook Share Code

For more Information visit Facebook Developer site: https://developers.facebook.com/docs/plugins/share-button/ 

Step 1: Include the JavaScript SDK on your page once, ideally right after the opening body tag.

<div id="fb-root"></div>
<script>(function(d, s, id) {
  var js, fjs = d.getElementsByTagName(s)[0];
  if (d.getElementById(id)) return;
  js = d.createElement(s); js.id = id;
  js.src = 'https://connect.facebook.net/en_US/sdk.js#xfbml=1&version=v2.11';
  fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));</script>

Step 2: Place this code wherever you want the plugin to appear on your page.

<div class="fb-share-button" data-href="https://developers.facebook.com/docs/plugins/" data-layout="button" data-size="small" data-mobile-iframe="true"><a class="fb-xfbml-parse-ignore" target="_blank" href="https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fdevelopers.facebook.com%2Fdocs%2Fplugins%2F&amp;src=sdkpreparse">Share</a></div>