$re = '/^([^\/]+)(\/.*.(js|css))$/';
$str = '1393435108/js/prototype/prototype.js,/js/prototype/window.js./,/js/scriptaculous/builder.js,/js/scriptaculous/effects.js,/js/scriptaculous/dragdrop.js,/js/scriptaculous/controls.js,/js/scriptaculous/slider.js,/js/lib/ccard.js,/js/prototype/validation.js,/js/varien/js.js,/js/mage/translate.js,/js/mage/adminhtml/hash.js,/js/mage/adminhtml/events.js,/js/mage/adminhtml/loader.js,/js/mage/adminhtml/grid.js,/js/mage/adminhtml/tabs.js,/js/mage/adminhtml/form.js,/js/mage/adminhtml/accordion.js,/js/mage/adminhtml/tools12345.js';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php