attrib_ereg.php

<?php

$subject = <<<DATA
property=value property2="value2" property3='value3'
DATA;

$pattern = '(
  (?:^|\s)
  (?<name>[a-z]\w+)
  (?:=)
  (?:(?J)
    (?:\'(?<value>[^\']+)\')|
    (?:"(?<value>[^"]*)")|
    (?<value>[^\s,]+)
  )
)xiu';

preg_match_all($pattern, $subject, $matches, PREG_SET_ORDER);

$result = [];
foreach ($matches as $match) {
  $result[$match['name']] = $match['value'];
}

var_dump($result);

preg to get an associative array from a htmlesqe attribute string