$re = '/(?:\?|&)(.+?)=([A-Z+%0-9]+)/im';
$str = 'http://mydomain/Forwards?searchValue[]=Nike+Webstore&searchValue[]=Bodyman&category_filter[]=Animals+%26+Pet+Supplies&category_filter[]=Fashion&country_filter[]=Aland+Islands&country_filter[]=American+Samoa
';
preg_match_all($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