将大写html标记转换为小写

Question

I have the following to replace uppercase HTML tags with lowercase ones.

$output = preg_replace("%<(/?[A-Z].*?)>%s",strtolower('$1'),$output);

The matching seems to be working well (in my RegEx testing site), but the replacement isn't.

<EM>TEST</EM> becomes EMTEST/EM

Hoping someone can point me in the right direction on this.

Answer 1

You are calling strtolower on "$1" and then using the result (which is just $1 again) to replace to.

Instead, use preg_replace_callback and have the callback be: function($m) {return strtolower($m[0]);}