title: get user's email id when user clicks on link
body: <p>I'm sending a link on gmail account.</p>
  
  <pre><code>analytics.com/get_email_address.php
  </code></pre>
  
  <p>On this php page,I'm trying to use <code>$_SERVER['HTTP_REFERER']</code> to get previous URL.But it's giving nothing.Please help me out to get previous URL when user click on the above link (from his gmail inbox).</p>
  
  <p>Actually I'm trying to fetch user's email id.If there is any other idea to get user's email id and domain name,please tell me.
  Thank You.</p>