$conf['feedbacktab_iframe_uri'] = 'http://example.com/';

I tried adding the following lines to my settings.php

<?php
$conf['feedbacktab_iframe_uri'] = 'http://example.com/';
?>

But the browser returns the following error message

Parse error: syntax error, unexpected '<' in /pathtomywebsitehere/sites/default/settings.php on line 229

I tried changing http://example.com/ for my website URL but the browser returns the same error message.

I tried adding the following line to my settings.php and it works. I removed the PHP tags.

$conf['feedbacktab_iframe_uri'] = 'http://example.com/';