Pixel Pete saysIn true XML mode, a single syntax error shows the dreaded "yellow screen of death" instead of the page.
When a browser parses application/xhtml+xml and hits any well-formedness error, it stops and shows a raw parse-error message — no partial render, no recovery. One unescaped ampersand from a CMS could blank an entire production page. This fatal-error behavior, more than anything, is why developers fled back to forgiving HTML.
Power-ups you unlock
One error → full parse failure (no render)
Browsers show a raw XML error screen
No graceful recovery in XML mode
This brittleness doomed XHTML in practice
Quirks Mode attacks — common mistakes
Underestimating how one stray char breaks everything
Trusting user/CMS content to stay well-formed
Choosing XML mode for content you can’t guarantee
Boss battleExplain why fatal errors made XHTML risky for content-managed sites.