I am trying to detect Arabic characters in a webpage\'s HTML using Notepad++ CTRL+F with regular expressions. I am entering the following as my search terms and it is return
This is happening because Notepadd++ regex engine is PCRE which doesn't support the syntax you have provided.
To match a unicode codepoint you have to use \x{NNNN} so your regular expression becomes:
\x{NNNN}
[\x{0600}-\x{06FF}]