title: How to force an HTML link to be absolute?
body: <p>In my website, users can put an URL in their profile.</p>
  
  <p>This URL can be <code>http://www.google.com</code> or <code>www.google.com</code> or <code>google.com</code>. </p>
  
  <p>If I just insert in my PHP code <code>&lt;a href="$url"&gt;$url&lt;/a&gt;</code>, the link is not always absolute.</p>
  
  <p>How can I force the <code>a</code> tag to be absolute ?</p>