Print node tags in html header I am trying to print the articles tags in the meta area of the html. I am able to print them, however, they contain all the markup, where as I just need the plain text, comma separated list, much like it prints when using the meta module. 
Here is what I am using. 

function mytheme_preprocess_html(&amp;$variables) {
if ($node = menu_get_object()) {  
  if ($node &amp;&amp; isset($node-&gt;nid)) {
  $node = node_load($node-&gt;nid);
   node_build_content($node);
   $variables['field_tags'] = render($node-&gt;content['field_tags']);
   }
 }
}
The reason your getting html in your output is because your using render(), which is just a wrapper for drupal_render. Per that function's documentation, it "Renders HTML given a structured array tree."

If you want just something like:
Cats, Dogs, Otters

it would probably be better to just pull out those values, ether by looping through the field_tags array and pulling out the value into an array and then imploding your array, or simply looping through and creating a string. So instead of render(), use something like:

$tags = array();
foreach($node-&gt;field_tags['und'] as $tag){
  $tags[] = $tag['value'];
}
$variables['field_tags'] = implode(',', $tags);