Question

I have the following code:

source = Regex.Replace(source, "<!--.*?-->", string.Empty, RegexOptions.Singleline | RegexOptions.IgnoreCase | RegexOptions.Compiled);

…and it works fine, except that it also strips away conditional comments:

<!--[if IE]>???<![endif]-->

Can someone tell me how to update the regex so it doesn’t remove conditional comments?

Answer 1

You can use negative lookaheads and negative look behinds:

<!--(?!\[).*?(?!<\])-->

Should only match <!-- not followed by [ and any --> not preceded by ], and of course, the .*? matches the text inbetween.

Tested using Derek Slager’s very useful and quick RegEx tester:

Source Text:

<!--[if IE]>???<![endif]--> 
<!--Comment--> 

Pattern:

<!--(?!\[).*?(?!<\])-->

Result:

Found 1 match:

1. <!--Comment-->