How to replace the first occurence with replaceRE function

[jinkuhu]

I need replace the first h2 with some extra attributes assigned to it.

Is it possible to replace only the first h2 with function replaceRE?

Thanks.

[davidsneighbour]

You need to know that the format for the regexp used is PCRE (noted in the docs) and then searching for “PCRE replace first occurence” brings some results… have a look if the answer(s) to this one help:

Regex: Select only the first instance of search results / first match