$args += array(
	'width' => '560',
	'height' => '315',
);

ob_start();
if (isset($args['src']))
{
?>
<iframe width="<?php echo htmlspecialchars($args['width'])?>" height="<?php echo htmlspecialchars($args['height'])?>" src="<?php echo htmlspecialchars($args['src'])?>" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<?php 
}

return ob_get_clean();