How to override $page_top variable? I am new to drupal 7 theming. I see that there is a variable called $page_top  in html.tpl.php file, which contains HTML markup for the header section of the body. I want to override this and print my markup. How can I do that in template.php file, or is there any other way?
You override markup by using :

  function template_preprocess_field(&amp;$vars){ 
    if($vars['element']['#field_name'] == 'field_event_geofield')
     {
          //kpr($vars); //Uncomment to output the $vars array.

           if(isset($vars['element']['#items']['0']['lat']) &amp;&amp; isset($vars['element']['#items']['0']['lon'])) { $vars['items']['0']['#markup'] = 'View Map'; } return; } 
           }