A B C

show code

<?php
$html = '<tr>       <td>A     </td>                <td>B   </td>      <td>C    </td>       </tr>';
$html = preg_replace('~(</td>)([\s]+)(<td>)~', '$1$3', $html);
$html = preg_replace('~(<tr>)([\s]+)(<td>)~', '$1$3', $html);
echo preg_replace('~(</td>)([\s]+)(</tr>)~', '$1$3', $html);