- preg_replace: documentation ( source)
<?php
$html = '<body>
<p style="text-align:left;text-indent:0pt;margin:12pt 0pt 12pt 0pt;"><span style="color:#000000;background-color:transparent;font-family:Times New Roman;font-size:12pt;font-weight:normal;font-style:normal;"> Какво да ви </span><span style="color:#000000;background-color:transparent;font-family:Times New Roman;font-size:12pt;font-weight:bold;font-style:normal;">кажа</span></p><p style="text-align:left;text-indent:0pt;margin:12pt 0pt 12pt 0pt;"><span style="color:#000000;background-color:transparent;font-family:Times New Roman;font-size:12pt;font-weight:bold;font-style:normal;">Не!</span></p></body>';
echo preg_replace('/style="[^"]*"/', '', $html);
php?>