Regex replace text outside html tags

Okay, try using this regex:

(text|simple)(?![^<]*>|[^<>]*</)

Example worked on regex101.

Breakdown:

(         # Open capture group
  text    # Match 'text'
|         # Or
  simple  # Match 'simple'
)         # End capture group
(?!       # Negative lookahead start (will cause match to fail if contents match)
  [^<]*   # Any number of non-'<' characters
  >       # A > character
|         # Or
  [^<>]*  # Any number of non-'<' and non-'>' characters
  </      # The characters < and /
)         # End negative lookahead.

The negative lookahead will prevent a match if text or simple is between html tags.

^([^<]*)<\w+.*/\w+>([^<]*)$

However this is a very naive expression. It would be better to use a DOM parser.