如果无法访问互联网，则显示静态图像

Question

I am working on a college website. I'm using a Facebook plugin to show the likes of a Facebook page by using this:

<iframe src="//www.facebook.com/plugins/likebox.php?href=https%3A%2F%2Fwww.facebook.com%2Fpcclahore&amp;width=364&amp;height=220&amp;show_faces=true&amp;colorscheme=light&amp;stream=false&amp;border_color&amp;header=true" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:364px; height:220px;" allowTransparency="true"></iframe>

The problem is that Facebook is blocked on the college servers, so nothing appears except a warning. Is it possible to show a static image instead of Facebook plugin while the internet not available (localhost) or Facebook not accessible? Like this:

if(Facebook accessible)
show Facebook pluging
else
<img src="images/fb.jpg" width="364" height="220">

Answer 1

// check if local server is HTTPS if so check Facebook HTTPS
$remote = ('80' !== $_SERVER['SERVER_PORT'])
    ? array('host' => 'ssl://www.facebook.com', 'port' => 443)  // HTTPS Facebook
    : array('host' => 'www.facebook.com', 'port' => 80);        // HTTP Facebook

$fp = @ fsockopen($remote['host'], $remote['port'], $errno, $errstr, 5);

echo (!$fp) // check if failed
    ? '<img src="images/fb.jpg" width="364" height="220">' // output local image
    : '<iframe src="//www.facebook.com/plugins/likebox.php?href=https%3A%2F%2Fwww.facebook.com%2Fpcclahore&amp;width=364&amp;height=220&amp;show_faces=true&amp;colorscheme=light&amp;stream=false&amp;border_color&amp;header=true" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:364px; height:220px;" allowTransparency="true"></iframe>'; // output IFRAME