title: Correctly set meta description in header.php
body: <p>I'm building a website with wordpress and a bought template. I added some functionality to the options/page creation. One can set a general meta description in the options and a meta description for each page while creating it.</p>
  
  <p>Although I'm entirely new to PHP, I managed to add everything necessary to my code. It wasn't all that hard and it works just fine. My questions are: Am I doing it right? How can I optimize my solution? What are the downsides of my approach?</p>
  
  <p><strong>HTML (header.php):</strong></p>
  
  <pre><code>&lt;?php
  // Defining a global variable
  global $page_meta_description;
  
  // Initializing the variable with the set value from the page
  $page_meta_description= get_post_meta($post-&gt;ID, MTHEME . '_page_meta_description', true);
  
  // Add meta tag if the variable isn't empty
  if ( $page_meta_description != "" ) { ?&gt;
      &lt;meta name="description" content="&lt;?php echo $page_meta_description; ?&gt;" /&gt;
  
  &lt;?php }
  
  // Otherwise add globally set meta description
  else if ( of_get_option('main_meta_description') ) { ?&gt;
      &lt;meta name="description" content="&lt;?php echo of_get_option('main_meta_description'); ?&gt;" /&gt;
  &lt;?php }
  
  // Set global meta keywords
  if ( of_get_option('main_meta_keywords') ) { ?&gt;
      &lt;meta name="keywords" content="&lt;?php echo of_get_option('main_meta_keywords'); ?&gt;" /&gt;
  &lt;?php } ?&gt;
  </code></pre>