extracting attributs from <element attr="value" attr2=val attr3='val'>

extract-attributes.php

<?php

// extracting attributes
// http://stackoverflow.com/questions/7776469/preg-match-with-name-being-last-in-input

$expected = array(
    'value' => 'joe',
    'type' => 'hidden',
    'name' => 'firstname',
);

$sources = array(
    '<input value="joe" type="hidden" name="firstname">',
    '<input value="joe" name="firstname" type="hidden">',
    '<input name="firstname" type="hidden" value="joe">',
    '<input name=firstname type="hidden" value=\'joe\'>',
);

// http://www.php.net/manual/en/reference.pcre.pattern.syntax.php
$pattern = "/\s+(?<name>[a-z0-9-]+)=(((?<quotes>['\"])(?<value>.*?)\k<quotes>)|(?<value2>[^'\" ]+))/i";

foreach ($sources as $source) {
    $result = array();
    preg_match_all($pattern, $source, $matches, PREG_SET_ORDER);

    foreach ($matches as $match) {
        $result[$match['name']] = $match['value'] ?: $match['value2'];
    }
    
    var_dump($source, $result == $expected);
}