title: Dynamic content of og:title Facebook meta tag
body: <p>I use session values to set the content of facebook meta tag :</p>
  
  <pre><code>&lt;meta property="og:title" content="&lt;?php print $_GET['p']; ?&gt;"/&gt;
  </code></pre>
  
  <p>when I view source of the website the html appears like this :</p>
  
  <pre><code>&lt;meta property="og:title" content="Alex Atalla"/&gt;
  </code></pre>
  
  <p>which means it is successfully filled the value of session value in the content of title meta tag.</p>
  
  <p>But when I use facebook debugger it says that :</p>
  
  <pre><code>Object Missing a Required Value:    Object at URL 'http://www.palestinianz.com/' of type 'website' is invalid because a required property 'og:title' of type 'string' was not provided.
  </code></pre>
  
  <p>what is the problem ?</p>