- trim: documentation ( source)
- preg_replace: documentation ( source)
<?php
echo $querystring = 'abc/\asas///sss/';
echo '<hr>';
//$querystring = preg_match_all('#/#', trim($querystring), $matches);
//var_dump($matches);
echo $querystring = preg_replace('/[\/]$/', ' รงรงรง', trim($querystring));