Regex Editor & Tester

This regex matches whitespace sequences in HTML that can be safely collapsed during minification, but only when located outside `<pre>` and `<textarea>` elements where whitespace is semantically significant. It uses atomic groups and a lookahead to verify that the matched whitespace is not followed by content inside a preformatted block before reaching end of input or a new `<pre>`/`<textarea>` tag. Ideal for HTML minifiers needing to reduce file size while preserving whitespace-sensitive content.