正则表达式以匹配包含以下内容的字符串 <br/> 但不是其他HTML标签？

Question

I want to find and match strings that contain no HTML tags but <br/> and all other normal characters ([^<>]+).

So basically, this match dismisses any string that contains '<' or '>' but not '<br/>'.

This is what I can come up with:

preg_match('@[(?:<br/>).]+@sU', $str, $match);

Obviously it doesn't work cause' I don't know what to put at the dot. Any ideas?

Answer 1

I would just do it backwards -- see if the string contains any <...> tag other than <br/> and dismiss it if it does. So:

preg_match(/<(?!br)/i, $str, $match);
if (!$match) we_are_good();

Answer 2

Why not...

@(?:[^<]|<br */>)*@

That is, any number of (a complete <br /> tag or any non-tag-opening character).