Match e-mail addresses not contained in HTML tag

Programmer Question

I need to highlight an email addresses in text but not highlight them if contained in HTML tags, content, or attributes.

For example, the string example@example.com must be converted to <a href="mailto:example@example.com">example@example.com</a>

But email addresses in the string <a href="mailto:example@example.com">example@example.com</a> must not be processed.

I've tried something like this regexp:

(?<![":])[a-zA-Z0-9._%-+]+@[a-zA-Z0-9._%-]+.[a-zA-Z]{2,6}(?!")

but it doesn't work properly.

Find the answer here