$re = '/(position|top|left|bottom|right):\s?(\w*);/';
$str = 'background-image: url(http://host.ru:8080/img/environment/circle_portret2.jpg); position: absolute; top: 73px; left: 93px; background-position: 0px 0px; background-repeat: initial initial; ';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($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