title: Facebook Invite Friends Box with iframes is not loading
body: <p>i created a facebook app name bitsutopia, i wanted to invite my friends to that app using php.
  i am using iframe in that app. i got this code from <a href="http://developers.facebook.com/docs/reference/fbml/request-form/" rel="nofollow">http://developers.facebook.com/docs/reference/fbml/request-form/</a> php script to show  invite friends box. but it is not working. code - </p>
  
  <pre><code>&lt;?php
  
      // Get these from http://developers.facebook.com
      $api_key = 'xxxx';
      $secret  = 'xxxx';
  
      // Names and links
      $app_name = "Bitsutopia";
      $app_url = "https://apps.facebook.com/bitsutopia/";
      $invite_href = "fb.php";
  
      require_once 'facebook.php';
  
      $facebook = new Facebook($api_key, $secret);
      $facebook-&gt;require_frame();
      $user = $facebook-&gt;require_login();
  
      if(isset($_POST["ids"])) {
          echo "&lt;center&gt;Thank you for inviting ".sizeof($_POST["ids"])." of your friends on &lt;b&gt;&lt;a href=\"http://apps.facebook.com/".$app_url."/\"&gt;".$app_name."&lt;/a&gt;&lt;/b&gt;.&lt;br&gt;&lt;br&gt;\n";
          echo "&lt;h2&gt;&lt;a href=\"http://apps.facebook.com/".$app_url."/\"&gt;Click here to return to ".$app_name."&lt;/a&gt;.&lt;/h2&gt;&lt;/center&gt;";
      } else {
          // Retrieve array of friends who've already authorized the app.
          $fql = 'SELECT uid FROM user WHERE uid IN (SELECT uid2 FROM friend WHERE uid1='.$user.') AND is_app_user = 1';
          //$_friends = $facebook-&gt;api_client-&gt;fql_query($fql);
  
          // Extract the user ID's returned in the FQL request into a new array.
          $friends = array();
          if (is_array($_friends) &amp;&amp; count($_friends)) {
              foreach ($_friends as $friend) {
                  $friends[] = $friend['uid'];
              }
          }
  
          // Convert the array of friends into a comma-delimeted string.
          $friends = implode(',', $friends);
  
          // Prepare the invitation text that all invited users will receive.
      $content =
      "&lt;fb:name uid=\"".$user."\" firstnameonly=\"true\" shownetwork=\"false\"/&gt; has started using &lt;a href=\"http://apps.facebook.com/".$app_url."/\"&gt;".$app_name."&lt;/a&gt; and thought it's so cool even you should try it out!\n".
      "&lt;fb:req-choice url=\"".$facebook-&gt;get_add_url()."\" label=\"Put ".$app_name." on your profile\"/&gt;";
  
  ?&gt;
  &lt;fb:serverfbml style="width: 650px;"&gt; 
       &lt;script type="text/fbml"&gt;
          &lt;fb:fbml&gt;
      &lt;fb:request-form
          action="&lt;?php echo $invite_href; ?&gt;"
          method="post"
          type="&lt;?php echo $app_name; ?&gt;"
          content="&lt;?php echo htmlentities($content,ENT_COMPAT,'UTF-8'); ?&gt;"&gt;
  
          &lt;fb:multi-friend-selector
              actiontext="Here are your friends who don't have &lt;?php echo $app_name; ?&gt; yet. Invite whoever you want -it's free!"
              exclude_ids="&lt;?php echo $friends; ?&gt;" /&gt;
      &lt;/fb:request-form&gt; 
          &lt;/fb:fbml&gt;
      &lt;/script&gt; 
  &lt;/fb:serverfbml&gt;
  &lt;?php
       }
  ?&gt;
  &lt;script src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/FeatureLoader.js.php" type="text/javascript"&gt;&lt;/script&gt;
  &lt;script type="text/javascript"&gt;
      FB_RequireFeatures(
           ["CanvasUtil"],
           function(){
               FB.XdComm.Server.init('/xd_receiver.html');
               FB.CanvasClient.startTimerToSizeToContent();
           }
      );
  &lt;/script&gt;
  
  &lt;script type="text/javascript"&gt;
      FB_RequireFeatures(["XFBML"], function(){ FB.Facebook.init("Your Facebook API Key", "/xd_receiver.html"); });   
  &lt;/script&gt;
  </code></pre>
  
  <p>the invite box is not appearing in the app page. anything wrong in this one?</p>