PHP正则匹配Öffnung失效求助：仅普通字符串可正常替换

The issue with your current regex is that the lookaround assertions aren't correctly identifying whether the word "Öffnung" is inside an HTML tag. A more reliable approach is to use preg_replace_callback to explicitly skip HTML tags while replacing the target word elsewhere.

Working Code #

$content = preg_replace_callback(
    '/(<[^>]+>|\bÖffnung\b)/s',
    function($matches) {
        // Return HTML tags unchanged
        if (str_starts_with($matches[0], '<')) {
            return $matches[0];
        }
        // Replace standalone "Öffnung" with the link
        return '<a href="">Öffnung</a>';
    },
    $content
);

How This Works #

1. Regex Breakdown: The regex /(<[^>]+>|\bÖffnung\b)/s matches two types of content:
   • <[^>]+>: Any full HTML tag (opening, closing, or self-closing) — this captures everything from < to >.
   • \bÖffnung\b: The standalone word "Öffnung" (using word boundaries to avoid partial matches like "Öffnungszeiten").
2. Callback Logic: For each match:
   • If the match is an HTML tag (starts with <), we return it exactly as it was.
   • If it's the word "Öffnung", we replace it with your desired link.

This approach ensures that "Öffnung" inside HTML tags (including attribute values like <a title="Öffnung">) is never replaced, while standalone instances are updated correctly.

Why Your Original Regex Failed #

Your original regex uses lookarounds that don't properly check the tag context:

• (?!((<.*?))): This negative lookahead checks that there's no < immediately after the current position, which doesn't prevent matches inside tags (e.g., <div>Öffnung has > before the word, not <).
• (?!(([^<>]*?)>)): This trailing lookahead checks for no non-tag characters followed by > after the word, but it doesn't account for closing tags that start with < (like </p>), so it would incorrectly allow replacement inside some tags.

Content of the question originates from Stack Exchange, question author Hữu Công Hoàng