<?php
$content = '<div><span class="smw smw-inline smw-basic smw-ct-default smw-visible" data-symbol="GSD.V" data-type="inline" data-refresh-frequency="5" data-source="live">
<span class="smw-market-data-field smw-field-l1" data-field="l1">0.65</span>
</span></div>';
echo $string = preg_replace('/<[^>]*>/', '', $content);
echo $new_string = preg_replace('/<span[^>]+\>/i', '', $content);
?>